In a bowl, beat the butter until creamy.

Add the granulated sugar and brown sugar, and beat well.

Add the cocoa powder and beat until combined.

Add the peanut butter and beat until smooth.

Add the vanilla and eggs, one at a time, beating well after each addition.

In a separate bowl, mix the flour, baking soda, and salt. Add to the batter and mix until well combined.

Shape the dough into a log about 2 inches (5 cm) in diameter using parchment paper. Remove the paper and cut into 1/2-inch (1.5 cm) thick slices. Press with a fork and decorate with a few peanuts on top.

Bake the cookies in a preheated oven at 375°F (190°C) for 10 minutes.

If desired, you can freeze the dough for later use, or use half now and freeze the rest.

Let the cookies cool on the baking sheet for a few minutes until firm enough to handle, then transfer to a wire rack to cool completely.