Preheat oven to 325°F.

Lightly grease donut pan or spray with nonstick cooking spray.

Using a medium bowl, add the flour, cocoa powder, baking powder, baking soda, salt and brown sugar; mix until well combined.

In a separate bowl, whisk together the buttermilk, egg, melted butter and vanilla extract.

Pour the buttermilk mixture into the flour mixture; stir until just combined. Fold the chocolate chips into the batter.

Spoon or pipe batter into donut pan. (Tip: Fill each donut circle about ⅔ full of batter.)

Bake at 325°F for 13-15 minutes, or until a toothpick inserted into a donut comes out clean. Let donuts rest in pan for 5 minutes and then invert pan and let donuts fully cool on wire rack.

Using a handheld mixer, beat together cream cheese and powdered sugar.

Add peanut butter; beat until well-combined.

Add whipped topping; beat until well combined.

Frost the tops of the cooled doughnuts and then sprinkle chopped peanut butter cups and chocolate sprinkles on top.