Make the fudge filling: Begin by preparing a batch of my Easy Hot Fudge Sauce according to the instructions provided on the designated recipe page. Once the sauce is fully cooked, whisk in 2 tablespoons of cocoa powder until smooth. Transfer the mixture into a jar or container and let it cool to room temperature. Then, refrigerate it for at least 4 hours or until it becomes fully set and firm.

Make the cookie dough: In a large mixing bowl, combine the softened butter with both the brown sugar and granulated sugar. Using a wooden spoon or rubber spatula, cream the mixture together until it becomes pale and fluffy. Add in the egg and vanilla extract and mix until the ingredients are thoroughly combined. In a separate medium bowl, sift together the flour, cocoa powder, baking soda, and salt, then whisk the dry ingredients until evenly blended. Add the flour mixture to the wet ingredients and gently fold it in just until no dry streaks remain. Cover the bowl and refrigerate the dough for 2 hours to allow it to firm up.

Form the fudge centers: Once the fudge filling is chilled, scoop out teaspoon-sized portions and drop them into a bowl filled with cocoa powder. Roll each fudge portion around in the cocoa powder until evenly coated. Place the coated fudge balls on a parchment-lined plate or tray and transfer them to the freezer for 30 minutes to firm up while the cookie dough continues to chill.

Assemble the cookies: Using a 1 ½-ounce cookie scoop, portion the chilled dough into 14 equal balls. Take one dough ball and place it in the palm of your hand, then flatten it gently into a disk about 2 ½ inches wide. Place one of the frozen fudge balls into the center of the disk and carefully wrap the cookie dough around it, sealing all edges to ensure the filling stays enclosed during baking. Repeat the process with the remaining dough and fudge centers. Arrange the stuffed dough balls on a tray and refrigerate them for another 15 minutes while preheating the oven.

Bake the cookies: Preheat your oven to 375°F (190°C) and line two large baking sheets with parchment paper. Arrange the chilled cookie dough balls on the prepared sheets, spacing them approximately 3 inches apart to allow room for spreading. Bake the cookies for 8–10 minutes, or until the edges are set and the tops appear matte while the centers remain slightly soft. Let the cookies cool completely on the baking sheets before serving.