Add cocoa powder, flour, salt and baking powder to a small bowl and stir to combine
Add butter, sugar, vanilla and eggs to a large bowl and mix with on low until combined
Pour the dry ingredients into the wet ingredients and mix well
Cover and refrigerate dough for at least one hour
Pour powdered sugar into a small bowl
Pre-heat oven to 350 degrees and line two large baking sheets with parchment paper
Drop dough by the spoonful into powdered sugar and roll around until well coated (dough will be sticky)
Place dough balls on baking sheets, leaving at least 1/2 inch space between
Bake for 10-12 minutes
Allow to cool for a few minutes before removing from pan to a cooling rack
