In a mixing bowl, combine 1 cup of creamy peanut butter, ½ cup of softened, melted butter, and ¾ cup of brown sugar. Beat these together until light and fluffy for about 2-3 minutes. Then, add 1 egg and 1 teaspoon of vanilla extract, mixing until well incorporated.

In a separate bowl, whisk together 1.5 cups of flour, ½ teaspoon of baking soda, and a pinch of salt, then gradually mix into your wet ingredients until just combined.

In another bowl, whisk ½ cup of melted butter with 1 cup of white sugar until smooth. Mix in ½ cup of cocoa powder, then add 1 egg and 1 teaspoon of vanilla extract, stirring until well combined.

Fold in ½ cup of all-purpose flour, ¼ teaspoon of baking powder, and a pinch of salt until just combined.

Cover both doughs with plastic wrap and refrigerate for about 30 minutes.

Use a cookie scoop or tablespoon to scoop 1-2 tablespoons of each dough, placing them side by side on your prepared baking sheet.

Gently swirl the two doughs together using a toothpick or skewer to create a marbled effect.

Preheat your oven to 350°F (175°C). Bake for 9-11 minutes until the tops appear crackly and edges are just set.

Remove the cookies from the oven and allow to cool on the baking sheet for 5-10 minutes before transferring to a wire rack to cool completely.