Put the butter in the bowl of a stand mixer and beat with a paddle until it becomes creamy. Add the sugars and beat for about 4 minutes, stopping occasionally to scrape sides of bowl.

With mixer on low speed, pour in the 100 grams of beaten eggs and the vanilla.

In a separate bowl mix together the flour, cocoa powder, baking soda, and salt. Add to the mixing bowl and stir on low until completely blended, then stir in the peanut butter chip mixture.

Scoop dough into 12 equal size mounds and place on a piece of plastic wrap. Cover and chill, cover with plastic wrap and chill for several hours (I recommend overnight) or until the dough is stiff.

Arrange oven rack so that it is in the top third of the oven.

Preheat oven to 375 degrees F. Line a baking sheet with parchment paper.

When ready to bake, arrange dough balls on a parchment lined baking sheet and bake at 375 F. for 16-18 minutes. Cookies should look slightly underdone. Allow cookies to cool on the baking sheet for about 5 minutes, then carefully transfer to a wire rack to finish cooling.