Marshmallow Krispies Brownies

1 box brownie mix
1 bag miniature marshmallows
1 1/2 cups semisweet chocolate chips
1 cup peanut butter
1 tablespoon butter
1 1/2 cups Rice Krispies cereal

Prepare and bake brownie mix as directed in a 9 x 13-inch pan. Sprinkle with marshmallows. Return to oven for 3 to 5 minutes. Cool in pan on rack.

In saucepan combine chocolate chips, peanut butter and butter. Heat and stir until chips are melted. Remove from heat and stir in Rice Krispies cereal. Pour evenly over marshmallows. Refrigerate until set. Serve at room temperature.