1 cup plus 2 tablespoons (255 grams) unsalted butter, at room temperature
1 cup (200 grams) sugar
1 cup (215 grams) light brown sugar
2 teaspoons vanilla extract
2 1/2 cups (350 grams) all-purpose flour
3/4 cups (62 grams) unsweetened cocoa powder
1 teaspoon baking soda
1/2 teaspoon salt
12 ounces (340 grams) semi-sweet chocolate chips (about two cups)
Preheat oven to 350 degrees F ( degrees C).
Add butter and sugars to a large bowl, turn a hand mixer to medium speed and beat until creamy, light and fluffy.
Add one egg, then turn mixer to medium and beat until well incorporated. Add the second egg as well as the vanilla extract and beat until they are well incorporated.
In a separate bowl, combine the flour, cocoa powder, baking soda and the salt with a whisk. Whisk at least 6 to 10 times.
With the hand mixer on low, slowly add the dry ingredients to the wet ingredients, scraping down the sides of the bowl as needed. The cookie batter will become very thick. You only need to mix until everything has combined.
Stir in the chocolate chips.
Drop cookie dough by rounded tablespoonfulls onto baking sheets. Bake 9 to 12 minutes or until the cookies have puffed a little and the tops are dry. Cool on baking sheets for 5 minutes then transfer to a cooling rack and cool completely.