Preheat oven to 350 degrees

in mixer bowl cream butter and brown sugar until light and fluffy

add in one egg at a time mixing completely after each addition

mix in vanilla

in separate bowl place cocoa powder, flour, baking soda, and salt and mix until well blended

add flour mixture to the mixer bowl with butter and brown sugar on low until fully combined

cover bowl with plastic wrap and place in the fridge until the dough is chilled, at least 30 minutes.

roll two tablespoons of dough into a ball, then into the sprinkles

place each ball of dough on a parchment-lined baking sheet 2 inches apart and bake for 9-11 minutes, edges will be slightly firm

allow cookies to cool on the baking sheet.