Preheat your oven to 350°F (175°C) and prepare a baking sheet with parchment paper.

In a bowl, combine the flour, baking soda, and salt, whisking them together thoroughly. Set aside.

In a separate large bowl, beat the softened butter with granulated and brown sugars until light and fluffy. Incorporate the egg and vanilla extract, mixing until well blended.

Slowly add the dry ingredients to the wet mixture, stirring gently until just combined. Fold in the creamy peanut butter and chocolate chips.

For the chocolate swirl, mix the cocoa powder, granulated sugar, melted butter, egg, and vanilla extract in another bowl until smooth.

Take spoonfuls of the cookie dough and place them on the prepared baking sheet, leaving about 2 inches of space between each mound. Create a swirl by adding a teaspoon of the chocolate mixture on top of each cookie dough ball.

Bake the cookies for 10-12 minutes, until the edges are firm but the centers remain slightly soft. Let them cool on the baking sheet for about 5 minutes before transferring to a wire rack to cool completely.