Make Peanut Butter Dough: In a mixing bowl, beat together the creamy peanut butter, softened butter, and brown sugar until light and fluffy. Add the egg and vanilla, mixing until well combined. In a separate bowl, whisk together the flour, baking soda, and salt, then gradually incorporate this dry blend into the wet ingredients until just combined.

Make Brownie Dough: In another bowl, whisk together melted butter, white sugar, and cocoa powder until smooth. Add the egg and vanilla, stirring until fully combined. Carefully fold in flour, baking powder, salt, and chocolate chips until there are no dry streaks visible.

Chill Both Doughs: Cover both doughs and refrigerate for 30 minutes.

Scoop and Swirl: On a lined baking sheet, drop 1-2 tablespoons of each dough side by side and swirl with a toothpick.

Bake: Preheat oven to 350°F (175°C) and bake cookies for 9-11 minutes.

Cooling: Allow cookies to cool on the baking sheet for 5-10 minutes before transferring to a wire rack.