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 to blend them. Set the mixing bowl aside.
Weigh or measure in a medium bowl 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 till light and fluffy. About 3 minutes and speed 6 on my KitchenAid. Turn the mixer off and scrape down the sides. Add the sugars and turn the mixer back to the six settings and beat till all the sugar is incorporated, about 2 to 3 minutes. Next, add the egg and the vanilla extract and beat one more minute.
Turn the mixer down low and slowly add the flour, cocoa powder, baking powder, and salt mixture to the butter, cream cheese. The batter will be very soft. Cover with plastic wrap and put into the refrigerator for at least an hour. I sometimes put it in the freezer for 15 minutes before moving the bowl to the fridge. Depending on how fast your oven heats up you can preheat at any time.
Line 2 cookie sheets with parchment paper and set aside. I have not used the silicone sheets with this cookie so not sure how they will turn out. Since I share my cookies with the people at work I use OXO Good Grips Cookie Scoop Small so everyone can have a cookie but you can use a OXO Good Grips Cookie Scoop Medium if you want bigger cookies. You may need to add a minute or 2 on the baking time.
Bake for 10-12 minutes. They will be very soft to the touch when you pull them out but leave them on the cookie sheet for a couple of minutes, and the tops will harden. Then move to a cooling rack to finish.