Peanut-Butter Swirl Brownies
Dollops of peanut butter filling are spooned onto brownie batter; pulling a knife back and forth through both results in a marbleized look.
To swirl brownies, work quickly so that batter and filling don't set. Use two large spoons to drop dollops of filling on the first layer of batter about one inch apart. Repeat with next layer of batter and remaining filling. Drag a butter knife back and forth through the layers with the tip touching the bottom of the pan.