Reese’s Pieces Chocolate Chip Cookie Bars

Introduction

Reese’s Pieces Chocolate Chip Cookie Bars are the ultimate fusion of two beloved American treats: classic chocolate chip cookies and the iconic peanut butter–candy crunch of Reese’s Pieces. These bars deliver a rich, buttery cookie base studded with melty semi-sweet chocolate chips and vibrant, peanut-buttery Reese’s Pieces candies—offering layers of texture, flavor, and nostalgia in every square. Unlike traditional drop cookies, these bars bake up uniformly thick and chewy, with crisp golden edges and a soft, gooey center that holds the candy pieces perfectly without bleeding or melting away. Whether you’re baking for a school bake sale, a tailgate party, a holiday dessert tray, or simply satisfying an after-dinner craving, these bars promise crowd-pleasing appeal, easy preparation, and irresistible peanut butter–chocolate synergy.

The History

The origin of Reese’s Pieces Chocolate Chip Cookie Bars lies at the delicious intersection of mid-century American confectionery innovation and home-baking ingenuity. Reese’s Pieces were introduced by The Hershey Company in 1978—two years after the release of E.T. the Extra-Terrestrial, whose iconic “Reese’s Pieces” scene catapulted the candy into pop-culture immortality. Almost immediately, home bakers began experimenting with incorporating the colorful, peanut-butter-filled candies into cookies, brownies, and bars—seeking to replicate the creamy-sweet contrast they loved in candy form within a baked good. While traditional chocolate chip cookies date back to Ruth Wakefield’s 1938 invention at the Toll House Inn, the Reese’s Pieces variation didn’t gain widespread traction until the late 1990s and early 2000s, when food bloggers, church cookbooks, and grocery store recipe cards began circulating hybrid versions. The bar format emerged as a practical evolution—offering consistent thickness, easier portion control, simplified cleanup, and superior candy distribution versus drop cookies (where Reese’s Pieces often sink or burn on the bottom). Today, this treat is a staple at potlucks across the Midwest and South, frequently featured in Hershey’s official recipe archives, and endlessly adapted by bakers seeking that perfect balance of salty-sweet, crunchy-chewy, and nutty-chocolaty satisfaction.

Ingredients Breakdown

Every ingredient in this recipe plays a precise functional and flavor role—no element is arbitrary. Let’s explore them in detail:

All-Purpose Flour (2 ¼ cups): Provides essential gluten structure. Measured correctly (spooned and leveled—not scooped!) to avoid dry, dense bars. A small amount of cornstarch (optional, 1–2 tbsp) can be added for enhanced tenderness and chew.
Baking Soda (1 tsp): Acts as the primary leavening agent, encouraging lift and spread while promoting golden-brown caramelization via Maillard reaction. It reacts with the brown sugar’s acidity for optimal rise.
Unsalted Butter (1 cup / 2 sticks, room temperature): Delivers richness, moisture, and flakiness. Room temperature ensures proper creaming with sugars—critical for air incorporation and texture. Salted butter may be used, but reduce added salt accordingly.
Granulated Sugar (¾ cup): Adds sweetness, aids in crisp edge formation, and contributes to structural stability through sugar crystallization during baking.
Packed Light Brown Sugar (1 cup): Brings deep molasses notes, moisture retention (for chewiness), and acidity to activate baking soda. Dark brown sugar may be substituted for a more robust, toffee-like flavor—but expect slightly denser bars.
Large Eggs (2, room temperature): Bind ingredients, add moisture and richness, and contribute to structure via protein coagulation. Room temperature eggs emulsify more smoothly into the butter-sugar mixture.
Pure Vanilla Extract (2 tsp): Enhances overall aroma and rounds out sweetness. Imitation vanilla works in a pinch, but pure extract delivers nuanced warmth and depth.
Semi-Sweet Chocolate Chips (1 ½ cups): Provide melty pockets of bittersweet cocoa. Use high-quality chips (e.g., Ghirardelli, Guittard) or finely chopped chocolate bars (60–65% cacao) for superior melt and flavor complexity.
Reese’s Pieces (1 ½ cups, plus extra for topping): The star! Their peanut butter centers stay intact when baked briefly, while their candy shells develop a delicate crackle and glossy sheen. Avoid substituting peanut M&Ms—they lack the same creamy interior and have a harder shell that doesn’t integrate as seamlessly.
Sea Salt Flakes (½ tsp, plus more for finishing): Balances sweetness and amplifies all other flavors. Fine table salt works, but flaky sea salt adds textural interest and controlled salinity.

Note on Add-Ins: A pinch of ground cinnamon (¼ tsp) or espresso powder (½ tsp) can deepen flavor without making it detectable—acting as a “flavor enhancer” much like umami in savory dishes.

Step-by-Step Recipe

Preheat & Prep: Position oven rack in the center position. Preheat oven to 350°F (175°C). Line a 9×13-inch metal baking pan with parchment paper, leaving a 2-inch overhang on two opposite sides for easy lifting. Lightly grease the parchment and exposed pan edges.
Mix Dry Ingredients: In a medium bowl, whisk together flour, baking soda, and fine sea salt. Set aside.
Cream Butter & Sugars: In a large stand mixer fitted with the paddle attachment (or using a hand mixer), beat room-temperature butter, granulated sugar, and brown sugar on medium-high speed for 3–4 minutes—until light, fluffy, and pale in color. Scrape down bowl halfway through. Proper creaming incorporates air, ensuring tender bars with even rise.
Add Eggs & Vanilla: Add eggs one at a time, beating on medium speed for 30 seconds after each addition until fully incorporated. Beat in vanilla until combined. Mixture should be smooth and homogenous—not curdled.
Incorporate Dry Ingredients: Reduce mixer speed to low. Gradually add dry ingredients in three additions, mixing just until no streaks of flour remain—about 15–20 seconds per addition. Do not overmix; overdevelopment of gluten leads to toughness.
Fold in Mix-Ins: Using a silicone spatula, gently fold in chocolate chips and 1 ½ cups Reese’s Pieces until evenly distributed. For optimal visual appeal and texture, reserve ⅓ cup Reese’s Pieces to press onto the surface before baking.
Spread & Smooth: Transfer dough to prepared pan. Use an offset spatula or the back of a spoon to spread evenly, pressing firmly into corners. Smooth top with damp fingers or a bench scraper for uniform thickness.
Top & Chill (Optional but Recommended): Sprinkle reserved Reese’s Pieces evenly over the surface, gently pressing them in. For thicker, chewier bars with less spread and intensified flavor, refrigerate batter in pan for 30–60 minutes. This solidifies the butter, slows initial melt, and enhances caramelization.
Bake: Bake for 28–34 minutes—rotating pan halfway through—until bars are deeply golden around the edges, the center looks set (not wet or shiny), and a toothpick inserted 1 inch from the edge comes out with moist crumbs (not raw batter). The center will continue to set as it cools. Do not overbake—even 1–2 extra minutes can cause dryness.
Cool Completely: Place pan on a wire rack and cool for at least 2 hours at room temperature. For cleanest cuts and best texture, refrigerate cooled bars for 1 hour before slicing. This firms the chocolate and peanut butter, preventing smearing.
Cut & Serve: Using a sharp chef’s knife wiped clean between cuts, slice into 12–16 bars (depending on preferred size). For elegant presentation, garnish with flaky sea salt and a few whole Reese’s Pieces.

Tips

Measure Flour Accurately: Use the “spoon-and-level” method—fluff flour in bag, spoon into measuring cup, then level with straight edge. Scooping compacts flour and adds up to 25% excess, resulting in tough, crumbly bars.
Butter Temperature Matters: Butter should be cool to the touch but yield slightly under gentle pressure—like softened cream cheese. Too warm = greasy, flat bars; too cold = poor creaming = dense texture.
Chill Before Baking: Even 20 minutes in the fridge significantly improves chewiness, reduces spread, and concentrates flavor. Overnight chilling yields bakery-style, ultra-thick bars with caramelized edges.
Don’t Skip the Parchment: Foil tears easily and doesn’t release cleanly. Parchment ensures flawless removal and prevents sticking—even with the stickiest peanut butter residue.
Rotate Your Pan: Ovens have hot spots. Rotating at the 15-minute mark guarantees even browning and prevents burnt corners.
Underbake Slightly: Pull bars from oven when the center still looks *just* underdone—it will finish cooking from residual heat. Overbaked bars lose their signature chew and become brittle.
Cooling Is Non-Negotiable: Cutting warm bars causes crumbling and smearing. Patience yields clean edges and ideal texture.
Use Metal Pans: Light-colored aluminum conducts heat evenly. Dark or nonstick pans absorb more heat—reduce temp by 25°F and check 3–5 minutes earlier.
Room-Temperature Eggs Prevent Separation: Cold eggs can cause the creamed butter-sugar mixture to seize or look grainy. If forgotten, place eggs in warm water for 5 minutes.
Store Smart: Keep bars airtight at room temperature for up to 4 days, refrigerated for up to 10 days, or frozen (unfrosted) for 3 months. Thaw overnight in fridge or at room temp for 1 hour.

Variations and Customizations

This base recipe is incredibly versatile—ideal for seasonal tweaks, dietary adaptations, and creative flair:

Double Peanut Butter: Add ½ cup creamy peanut butter to the creamed butter-sugar mixture for amplified nuttiness. Reduce butter by 2 tbsp to compensate.
Reese’s Peanut Butter Cups Edition: Replace half the chocolate chips with chopped mini Reese’s Peanut Butter Cups. Press whole minis onto the surface before baking for decadent pockets.
Oatmeal-Pieces Bars: Substitute 1 cup of flour with old-fashioned rolled oats (not instant) and add 1 tsp ground cinnamon for cozy, chewy depth.
White Chocolate & Peanut Butter Swirl: Melt ½ cup white chocolate and swirl into batter before adding mix-ins for marbled elegance.
Spiced & Smoky: Add ½ tsp smoked paprika + ¼ tsp ground ginger for a subtle, sophisticated warmth that complements peanut butter beautifully.
Gluten-Free: Use a 1:1 gluten-free flour blend (like King Arthur or Bob’s Red Mill) + ½ tsp xanthan gum (if not included). Increase chill time to 90 minutes for optimal structure.
Vegan Adaptation: Substitute butter with vegan butter (Miyoko’s or Earth Balance), flax eggs (2 tbsp ground flax + 6 tbsp water, rested 10 mins), and dairy-free chocolate chips. Ensure Reese’s Pieces are vegan—note: standard Reese’s Pieces contain confectioner’s glaze (shellac), which is not vegan; seek certified vegan alternatives like Unreal Peanut Butter Cups or homemade candy-coated peanut butter bites.
Mini Bar Bites: Press batter into a lined 8×8-inch pan and bake 22–26 minutes. Cut into 24 petite squares—perfect for parties or lunchboxes.
Stuffed Center: After spreading batter, press a thin layer of peanut butter (¼ cup) into the center, then cover with remaining batter before topping with candy.
Holiday Edition: Add ½ tsp peppermint extract + crushed candy canes (in place of some Reese’s Pieces) for a festive twist—or swap in red/green Reese’s Pieces for Christmas.

Health Considerations and Nutritional Value

While undeniably indulgent, understanding the nutritional profile helps inform mindful enjoyment. Per standard 2″ × 2″ bar (based on 16 servings):

Calories: ~285 kcal
Total Fat: 15g (9g saturated, primarily from butter and chocolate)
Cholesterol: 45mg
Sodium: 180mg (moderate—easily reduced by cutting added salt by half)
Total Carbohydrates: 35g (26g sugars, including natural sugars from brown sugar and candy coatings)
Dietary Fiber: 1g (low—boost with oat or whole wheat flour substitutions)
Protein: 3g (minimal—enhance with peanut butter addition or protein-enriched flour)

Key Considerations:

Allergens: Contains peanuts, tree nuts (in some chocolate brands), milk, eggs, soy (lecithin in chocolate), and wheat. Always verify labels—especially for Reese’s Pieces, which carry “may contain tree nuts” warnings due to shared facilities.
Sugar Content: Reese’s Pieces contribute significant added sugar (~14g per ¼ cup). For lower-sugar options, reduce candy by ⅓ and increase chocolate chips—or use unsweetened cacao nibs for bitterness and crunch.
Portion Control: Bars are calorie-dense. Serving size awareness supports balanced intake—pair with fruit or yogurt for a more rounded snack.
Nutrient Gaps: Lacks significant vitamins/minerals beyond trace iron and magnesium from cocoa. Enrich with chopped walnuts (omega-3s), dark chocolate (>70% cacao), or a sprinkle of chia seeds.
Dietary Restrictions: Not inherently vegan, gluten-free, or low-FODMAP. However, thoughtful substitutions (as noted above) make it adaptable for many needs—with attention to cross-contamination risks.

Remember: Occasional enjoyment of treats like these supports psychological well-being and sustainable eating habits—balance, variety, and pleasure are pillars of holistic nutrition.

Ingredients

2 ¼ cups (280g) all-purpose flour, spooned and leveled
1 teaspoon baking soda
½ teaspoon fine sea salt
1 cup (227g / 2 sticks) unsalted butter, room temperature
¾ cup (150g) granulated sugar
1 cup (200g) packed light brown sugar
2 large eggs, room temperature
2 teaspoons pure vanilla extract
1 ½ cups (270g) semi-sweet chocolate chips
1 ½ cups (210g) Reese’s Pieces candies, plus ⅓ cup for topping
Flaky sea salt, for finishing (optional)

Directions

Preheat oven to 350°F (175°C). Line a 9×13-inch metal baking pan with parchment paper, leaving overhang on two sides; lightly grease.
In a medium bowl, whisk together flour, baking soda, and ½ tsp fine sea salt. Set aside.
In a large bowl using a stand or hand mixer, beat butter, granulated sugar, and brown sugar on medium-high until light, fluffy, and pale—about 3–4 minutes. Scrape bowl.
Add eggs one at a time, beating 30 seconds after each. Beat in vanilla until combined.
Reduce speed to low. Gradually add dry ingredients in three parts, mixing just until incorporated. Do not overmix.
Fold in chocolate chips and 1 ½ cups Reese’s Pieces with a spatula until evenly distributed.
Transfer dough to prepared pan. Spread evenly and smooth top. Press reserved ⅓ cup Reese’s Pieces onto surface.
(Optional but recommended) Refrigerate pan for 30–60 minutes.
Bake 28–34 minutes, rotating pan halfway, until edges are deep golden and center is set with moist crumbs on a toothpick.
Cool completely in pan on a wire rack—minimum 2 hours. For cleanest cuts, refrigerate 1 hour before slicing.
Using a sharp knife, cut into 12–16 bars. Garnish with flaky sea salt if desired. Store airtight.

FAQ

Can I use peanut butter chips instead of Reese’s Pieces?: Yes—but texture and flavor differ significantly. Peanut butter chips melt into ribbons and lack the candy shell’s crunch and visual pop. For closest results, use Reese’s Pieces exclusively.
Why did my Reese’s Pieces melt into blobs?: Likely causes: oven too hot, batter too warm before baking, or overbaking. Chill dough thoroughly and verify oven temperature with an oven thermometer.
Can I freeze the unbaked dough?: Absolutely. Press dough into pan, cover tightly, and freeze up to 3 months. Bake from frozen—add 5–8 minutes to bake time and cover edges with foil if browning too fast.
My bars turned out cakey—what went wrong?: Overmixing the batter after adding flour develops excess gluten. Also, too much leavening (extra baking soda) or expired soda can cause sponginess.
Are Reese’s Pieces gluten-free?: Yes—standard Reese’s Pieces are certified gluten-free by Hershey’s (though always verify packaging, as formulations can change).
Can I make these dairy-free?: Yes—with dairy-free butter, egg replacer (like Bob’s Red Mill Egg Replacer), dairy-free chocolate chips, and verified dairy-free candy (note: standard Reese’s Pieces contain milk solids and are not dairy-free).
How do I prevent the bars from sticking to the pan?: Parchment + light greasing is foolproof. Avoid spraying only—spray alone isn’t sufficient for sticky peanut butter residues.
Can I add nuts?: Yes! Fold in 1 cup chopped roasted peanuts or pecans with the chocolate and candy for extra crunch and protein.
What’s the best way to reheat a bar?: Wrap in a damp paper towel and microwave for 8–10 seconds—melts chocolate slightly and restores chewiness without drying.
Why do some recipes use cornstarch?: Cornstarch inhibits gluten formation and increases moisture retention—yielding softer, more tender bars. Add 1–2 tbsp with the dry ingredients for a notable difference.

Summary

Reese’s Pieces Chocolate Chip Cookie Bars are a nostalgic, crowd-pleasing hybrid dessert that masterfully balances buttery cookie richness, melty chocolate depth, and the unmistakable sweet-salty crunch of peanut butter–filled candies—all baked into thick, chewy, golden-edged bars with minimal effort.

With precise ingredient ratios, smart technique (especially chilling and proper cooling), and endless customization potential—from vegan adaptations to holiday twists—this recipe delivers consistent, bakery-quality results that satisfy cravings, spark joy, and earn rave reviews at every gathering.