In a large bowl, cream together the butter and sugars until light and fluffy.
½ cup unsalted butter, ½ cup sugar, ½ cup brown sugar
Beat in the egg and vanilla and continue mixing until combined. Scrape down the sides of the bowl as needed.
1 egg, 1 teaspoon vanilla
In a separate medium bowl, add the flour, cocoa powder, and salt and mix.
1 cup flour, ½ cup + 2 Tb unsweetened cocoa powder, ½ teaspoon salt
Add the dry ingredients into the wet ingredients, slowly. The dough will be thick.
1 teaspoon baking soda, ¼ teaspoon salt
Using a spoon, mix in the milk then fold in the chocolate chips.
½ cup dark chocolate chips, 2 Tablespoons milk
To make the peanut butter cookie dough
In a large bowl, cream together the butter and sugars until light and fluffy.
½ cup unsalted butter, ½ cup brown sugar, ¼ cup sugar
Beat in the peanut butter, then the egg, and then the vanilla (in that order). Scrape down the sides of the bowl as needed.
1 egg, ¾ cup peanut butter, 1 teaspoon vanilla
Mix in the baking soda and flour until just combined.
1/2 teaspoon baking soda, 1¼ cup flour
Fold in the chocolate chips.
½ cup dark chocolate chips
Chill both doughs for at least 1-2 hours. I did mine overnight.
Preheat the oven to 350 degrees and line a baking sheet with a silicone baking mat and set aside.
Using a cookie scoop (it's best to use 2 cookie scoops - one for each dough), scoop one chocolate and one peanut butter. Roll each dough into balls them smush them together and roll into a large ball. I did 8 per pan since they're pretty large.
Bake the cookies for 11-12 minutes. The cookies will look soft and underdone, but they will continue to cook on the pan after you take them out.
After about 5 minutes, transfer the cookies to a wire rack to finish cooling.