1Stir together butter, sugar and 1 teaspoon vanilla in large bowl.
Add 2 eggs; stir until blended. Stir together flour, cocoa, baking powder and salt.
Add to egg mixture, stirring until blended. Spread in a greased 13 X 9 inch baking pan.
Bake at 350 degrees for 18 to 20 minutes.
2Meanwhile, stir together sweetened condensed milk, peanut butter, remaining egg and 1 teaspoon vanilla.
Pour evenly over hot brownies. Sprinkle milk chocolate chips and peanut butter chips over peanut butter mixture.
Return to oven; continue baking 20 to 25 minutes more or until peanut butter layer is set and edges begin to brown.
Cool completely in pan on wire rack.