Whisk the flour, cocoa powder, baking powder, and salt in a large mixing bowl. Set aside.
1 cup flour, 5 oz unsweetened cocoa powder, ⅛ teaspoon salt
In a medium mixing bowl, cream the butter, sugars, egg, and vanilla until fluffy.
½ cup butter, ½ cup granulated sugar, ½ cup brown sugar, 1 egg, 1 teaspoon vanilla extract
Slowly add the dry ingredients to the bowl of creamed butter & sugars mixture until the flour mixture is blended in. Add the chocolate chips to the cookie dough and stir in with a spatula or wooden spoon. Distribute the chips evenly.
½ cup semi sweet chocolate chips, ½ cup white chocolate chips
Roll the cookie dough into balls, about 36 total. Put the powdered sugar in a bowl, and break up and big lumps. Set it next to another bowl with the ¼ cup of granulated sugar.
1 cup powdered sugar, ¼ cup granulated sugar
Roll the cookie dough balls first in the granulated sugar, then roll generously in the powdered sugar. Place on the parchment lined cookie sheet.
Leave about 2" between cookies, and set the tray in the preheated oven. Bake for 9 minutes at 350 F. Remove from oven and cool 5 minutes before transferring to a cooling rack.