2 cups sugar
1 cup butter, softened
2 tsp vanilla extract
1 1/2 cups flour
3/4 cup unsweetened cocoa powder
1 tsp baking powder
1/2 tsp salt
1 cup peanut butter chips
Preheat oven to 350 degrees.
Grease a 13 x 9-inch baking pan; set aside.
In a large bowl combine sugar and butter, beating until light and fluffy. Add the eggs, one at a time, beating well after each one. Stir in the vanilla.
In a small bowl combine the flour, cocoa powder, baking powder and salt; gradually add to the sugar mixture blending well.
Stir the peanut butter chips into the mixture with a large silicone spatula or wooden spoon.
Peanut Butter Mixture:
3/4 cup peanut butter
1/3 cup butter, softened
1/3 cup sugar
2 tbsps flour
3/4 tsp vanilla
In a small bowl combine the peanut butter and butter, beating until smooth. Add the sugar and flour, blending well. Add vanilla and eggs; beat until smooth.
Spread half of the chocolate mixture into the prepared pan. Spread the peanut butter mixture evenly over the brownie mixture. Spread the remaining brownie mixture over the peanut butter mixture. Pull a knife through the layers, curving to marble.
Bake at 350 degrees for 40 to 50 minutes or until the top springs back when lightly touched in the center and sides are beginning to pull away from the pan.
Set on a wire rack to cool completely.
3 squares (1-oz each) unsweetened chocolate
3 tbsps butter
2 2/3 cups powdered sugar
1/4 tsp salt
3/4 tsp vanilla extract
4 to 5 tbsps water
In a medium saucepan over low heat, melt the chocolate with the butter stirring constantly until smooth; remove from heat.
Stir the powdered sugar, salt, vanilla, and enough water for desired spreading consistency into the chocolate mixture.
Frost brownies and cut into bars.