Ingredients
Method
- Preheat oven to brownie box temperature; foil-line 9x13 pan and lightly spray.
- Prepare brownie batter per box; stir in optional chocolate chips.
- Spread batter evenly in pan. Dollop warm peanut butter on top; sprinkle powdered sugar over it.
- Swirl peanut butter into batter with knife to marble.
- Bake per box time, checking at lower end, until toothpick has a few moist crumbs.
- Cool completely in pan; lift with foil and cut bars.
