Preheat your oven to 350°F (177°C) and line a standard 12-cup muffin tin with paper cupcake liners.

In a large mixing bowl, using either a handheld mixer or a stand mixer fitted with the paddle attachment, cream the softened butter and granulated sugar together on medium-high speed until light and fluffy, about 2 minutes. Be sure to scrape down the sides and bottom of the bowl as needed. Add the eggs and vanilla extract, then continue mixing on medium-high speed until everything is well blended, about 1 minute. Scrape the bowl again to ensure even mixing. Set aside.

In a separate medium bowl, whisk together the flour, baking powder, and salt. With the mixer on low speed, gradually add the dry ingredients into the wet mixture. Slowly pour in the milk, followed by the fresh lemon juice and lemon zest. Mix just until everything is incorporated. Do not overmix, as this can affect the texture of the cupcakes.

Divide the batter evenly among the 12 cupcake liners, filling each about two-thirds full. Bake in the preheated oven for 18 to 22 minutes, or until a toothpick inserted into the center comes out clean. If making mini cupcakes (about 30), reduce baking time to 11–13 minutes but keep the oven temperature the same. Once baked, remove the cupcakes from the oven and allow them to cool completely. For best results, let them cool entirely in the pan before removing.

Once cooled, frost the cupcakes generously with vanilla buttercream. If you plan to garnish with lemon zest, add it just before serving to maintain freshness and visual appeal. Depending on how much frosting you use per cupcake, you may have some left over.

Store any leftover cupcakes tightly covered in the refrigerator for up to 3 day