1. Make the Peanut Butter Dough: A Creamy, Nutty Base

1. Cream Butter and Sugar: In a medium bowl, beat together the creamy peanut butter, softened butter, and packed brown sugar with an electric mixer (handheld or stand mixer) until the mixture is light and fluffy, about 2-3 minutes.
2. Add Egg and Vanilla: Beat in the egg and vanilla extract until well combined.
3. Combine Dry Ingredients: In a separate bowl, whisk together the all-purpose flour, baking soda, and salt.
4. Gradually Add Dry to Wet: Gradually add the dry ingredients to the wet ingredients, mixing on low speed or with a rubber spatula until just combined. Be careful not to overmix.
5. Chill Dough: Cover the bowl with plastic wrap and refrigerate for at least 30 minutes. Chilling the dough makes it easier to handle and helps prevent the cookies from spreading too much during baking.

2. Make the Brownie Dough: A Rich and Fudgy Counterpart

1. Combine Melted Butter and Sugar: In a separate medium bowl, whisk together the melted butter and white sugar until well combined.
2. Add Cocoa Powder: Beat in the cocoa powder until the mixture is smooth and there are no lumps.
3. Incorporate Egg and Vanilla: Add the egg and vanilla extract and whisk until well combined.
4. Add Dry Ingredients: In a small bowl, whisk together flour, baking powder, and salt. Gently fold the dry ingredients into the wet ingredients along with the chocolate chips, mixing until no dry streaks remain. Be careful not to overmix.
   • Tip: The brownie batter will be thicker than the peanut butter dough.
5. Chill Dough: Cover the bowl of brownie batter with plastic wrap and refrigerate for at least 30 minutes.

3. Assemble the Cookies: Creating the Marbled Effect

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Line Baking Sheets: Line two baking sheets with parchment paper.
3. Scoop Dough: Once both doughs are chilled, scoop out portions of each dough, using about 1-2 tablespoons of each.
   • Tip: You can use a cookie scoop for uniform size, or simply use a spoon.
4. Place Side by Side: Place a scoop of peanut butter dough and a scoop of brownie dough side by side on the prepared baking sheet.
5. Swirl Together: Use a toothpick or a skewer to gently swirl the two doughs together, creating a marbled effect. Don’t over-swirl, or the colors will become muddy.
   • Tip: You can also slightly roll the two dough balls together before placing on the baking sheet.
6. Space Apart: Repeat with the remaining dough, leaving about 2 inches between each cookie to allow for spreading.

4. Bake to Perfection: Achieving a Chewy and Fudgy Texture

1. Bake: Bake in the preheated oven for 9-11 minutes.
2. Check for Doneness: The cookies are done when the tops are lightly crackly and the edges are just set. The centers will still be quite soft.
   • Tip: Don’t overbake, or the cookies will be dry.

5. Cool and Enjoy: Savoring the Flavor Fusion

1. Cool on Baking Sheet: Let the cookies cool on the baking sheet for 5-10 minutes before transferring them to a wire rack. This allows them to firm up slightly.
2. Cool Completely: Transfer the cookies to a wire rack to cool completely.
3. Serve: Enjoy your Peanut Butter Brownie Swirl Cookies!