Chocolate Peanut Butter Squares aka "Reese's Bars"

I'm posting this recipe because I received so many requests for it after the church supper last week. I can't take any credit for it--just followed it exactly as printed in my old church's cookbook.

1 1/2 cups graham cracker crumbs

3 1/2 cups powdered sugar (you could maybe use a little less than this)

2 sticks butter/margarine, melted

1 cup creamy peanut butter

1 teaspoon vanilla

1 (12 oz) package semi-sweet chocolate chips

Combine graham cracker crumbs, powdered sugar, butter, peanut butter, and vanilla in large bowl. Press evenly into 9x13 pan. Melt chocolate chips in microwave or on stovetop. Spread melted chocolate evenly on top of crumb mixture. Let cool in fridge (about 30 minutes). Cut into small squares (but leave them in pan). Let cool completely in fridge. Keep cold until ready to serve.