Step 1: Make the Peanut Butter Dough

1. In a large mixing bowl, beat together the creamy peanut butter, softened butter, and brown sugar using a hand mixer or stand mixer until light and fluffy.

2. Add the egg and vanilla extract and beat until fully incorporated.

3. In a separate bowl, whisk together the flour, baking soda, and salt.

4. Gradually add the dry ingredients to the wet mixture. Mix on low speed until just combined. Do not overmix.

5. Set aside.

Step 2: Make the Brownie Dough

1. In a second bowl, whisk the melted butter and white sugar together until smooth.

2. Add the cocoa powder and whisk until fully incorporated.

3. Mix in the egg and vanilla extract.

4. In another small bowl, whisk together the flour, baking powder, and salt.

5. Fold the dry ingredients into the wet mixture using a spatula until no dry streaks remain.

6. Stir in the chocolate chips.

Step 3: Chill the Doughs

1. Cover both doughs and chill in the refrigerator for 30 minutes. This helps firm the doughs and ensures clean swirls during baking.

Step 4: Form the Swirl Cookies

1. Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper.

2. Using a cookie scoop or tablespoon, scoop 1–2 tablespoons of each dough (peanut butter and brownie).

3. Press the two doughs together gently into one rough ball. Place on the baking sheet.

4. Use a toothpick or skewer to gently swirl the doughs together on top, creating a marbled effect. Don’t over-swirl—2–3 swirls is perfect.

Step 5: Bake

1. Bake the cookies for 9–11 minutes, or until the tops are crackly and the edges are just set.

2. The centers should still be slightly soft and appear slightly underbaked—that’s what gives them a gooey center.

Step 6: Cool and Serve

1. Let the cookies cool on the baking sheet for 5–10 minutes to finish setting.

2. Transfer to a wire rack to cool completely.

3. Enjoy warm or store for later!