Grease your brownie pan - I use butter, but feel free to use whatever fat you'd like. An 8 x 8 brownie pan would be ideal for this recipe, but I just used one of my Pyrex baking dishes.
Crumble peanut butter cups.
Mix together all dry ingredients (including peanut butter cup pieces) in a medium bowl.
Mix wet ingredients together and pour into dry ingredients.
Stir until just combined.
Pour batter into brownie pan and distribute evenly.
Bake at 325 for 40-45 minutes or until a toothpick comes out almost clean. Start checking after 30 minutes. You don't want to overcook to overcook the brownies - slightly underdone is preferable to slightly overdone.