1/2 cup butter or margarine
3/4 cup Reese's Creamy Peanut Butter
1 3/4 cups granulated sugar
1 1/2 teaspoons vanilla extract 
4 eggs, slightly beaten
1 1/2 cups all-purpose flour
1/2 teaspoon baking powder
1/4 teaspoon salt
2 cups semisweet chocolate chips

Preheat oven to 350 degrees F. Grease a 13 x 9-inch baking pan.

Melt butter. Add peanut butter; stir until melted. Stir in sugar and vanilla extract. Add eggs; with spoon, stir until well blended. Add flour, baking powder and salt; stir until blender. Stir in chocolate chips. Spread batter into prepared pan. Bake 35 minutes or until top is golden brown and edges are firm.

Cool completely in pan on wire rack. Cut into bars. Add ice cream and top with your favorite syrup to make a super sundae.