01 -
In a large mixing bowl, cream together the softened butter, peanut butter, granulated sugar, and brown sugar until light and fluffy (about 3-4 minutes). Add the egg and vanilla extract, beating until fully incorporated. In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add these dry ingredients to the wet mixture, stirring just until combined. Set aside.
02 -
In another large bowl, combine the melted butter with granulated sugar and whisk until well mixed. Add the egg and vanilla extract, mixing thoroughly. Sift together the cocoa powder, flour, baking powder, and salt, then gradually stir these into the wet ingredients until the dough is smooth and uniform.
03 -
Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Take about 1 tablespoon of each dough (peanut butter and brownie) and roll together into a ball. Gently twist the doughs together to create a marbled effect but avoid overmixing to maintain distinct swirls.
04 -
Place the dough balls on the prepared baking sheet, spacing them about 2 inches apart. Bake for 10-12 minutes, or until the edges are just set but the centers are still soft.
05 -
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.