Weigh or measure into a medium bowl your flour, cocoa powder, baking powder, and salt. After all the ingredients are in the bowl, run a whisk through the dry ingredients to blend. Set the mixing bowl aside. Next, weigh or measure the white and the light brown sugar. Set this bowl aside, also.
In a stand or hand-held mixer, beat the cream cheese and butter until light and fluffy, about 1 to 2 minutes, on a medium mixer speed. Turn the mixer off and scrape down the sides. Add the sugars and beat for about 2 to 3 minutes on a medium mixer speed. Next, add the egg and the vanilla extract and incorporate.
Turn the mixer down low and slowly add the flour, cocoa powder, baking powder, and salt mixture. The batter will be very soft.
Preheat your oven to 350°F (175°C or 180°C) and put mini cupcake wrappers in your mini cupcake pan. If your pan is 24 cups, it will take two bakes. However, if you have a 48-cup pan, you can do this in one bake.
I do not chill this cookie dough because I want the dough to spread in the mini cupcake wrapper. I use a medium cookie scooper to add one scoop to a mini cupcake wrapper.
Bake for 11-13 minutes. They will be very soft to the touch when you pull them out but leave them in the pan for a minute. I use a knife to lift each mini wrapper out of the pan. Then move to a cooling rack to finish.