Preheat the oven to 350 degrees F (180 degrees C).
Spray the bottom of a 13 x 9-inch baking dish with nonstick cooking spray.
In a medium bowl, stir
Brownie Mix (1 box)
Water (1/4 cup)
Vegetable Oil (1/2 cup)
Large Eggs (2)
until well blended and transfer to the greased baking dish.
In a small microwavable bowl, microwave the
Creamy Peanut Butter (3/4 cup)
, uncovered, for 30 seconds until softened, then stir.
Dollop 15-20 spoonfuls of peanut butter in 5 x 4 rows over the brownie batter. For a marbled design, pull a knife through the batter and fill about 1 inch apart; turn the baking dish and repeat.
Bake for 25 to 30 minutes or until a toothpick inserted to the center comes out clean.
Let the brownies cool for 10-15 minutes. Slice up and serve.