Preheat the oven to 350 F. Line 2 baking pans with parchment paper, if desired.

In a large mixing bowl, cream together the peanut butter, butter, sugar and brown sugar. Beat together until smooth & creamy best if using a stand mixer or hand mixer.

Add the egg and vanilla extract and continue to mix until well combined.

In a small mixing bowl, whisk together the flour, cocoa powder, baking soda and salt. Stir in the flour mixture to the butter and sugar mixture and mix until well combined. Stir in chocolate chips.

Using a cookie dough scooper or making the dough into 1 inch balls. Roll in white granulated sugar if you desire and place on to baking sheet.

Using a fork, press down on each ball of dough to slightly flatten and creating a criss-cross pattern.

Bake for 8-9 minutes. Let cool on the baking sheet for a few minutes and then transfer to a wire rack.

These keep well for a couple of days in an airtight container.