Creating these cookies is as joyful as sharing them. Follow these steps:

1. Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.
3. In a large mixing bowl, cream together the butter, granulated sugar, and brown sugar until light and fluffy, about 3 minutes.
4. Add the egg and vanilla extract to the butter mixture, beating until well combined.
5. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
6. Divide the dough in half. To one half, add the peanut butter and mix until smooth. To the other half, fold in the chocolate chips if using.
7. Take a tablespoon of each dough and gently swirl them together in your hands to form a ball. Place on the prepared baking sheet.
8. Bake for 10-12 minutes, or until the edges are set and the centers are slightly soft.
9. Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

Remember, my grandmother always said the best cookies come from a place of patience and love. Enjoy the process and the memories you create along the way.