In a medium bowl, mix together cocoa powder, flour, baking powder, and salt to combine the dry ingredients.
Mix wet components: Put butter and sugar in a huge bowl and use an electric mixer to combine. One by one, add the eggs and blend on medium-low speed for around 10 seconds each.
Mix the egg mixture on low speed, gradually adding the dry ingredients until they are fully incorporated.
Cover the bowl and refrigerate the cookie dough for a minimum of 1 hour or up to overnight. The longer you chill it, the thicker the cookies will be.
Preheatoven to 350°F. Place powdered sugar in a medium bowl. Take tablespoon-sized pieces of cookie dough and roll in sugar. Bake when ready.
Bake:Line a baking sheet with parchment paper, placing the cookies with enough space between them.
Bakefor 10-15 minutes, or until the cookies have spread and cracked. Allow them to cool on the baking sheet for 5 minutes before transferring them to a cooling rack for complete cooling.
