Peanut Butter Cup

1 1/2 c graham cracker crumbs
1 box powdered sugar [amount?]
1 1/2 c peanut butter
2 sticks margarine
1 package chocolate chips

Mix crumbs with sugar. Melt peanut butter and 1 1/2 sticks butter. Mix with crumb mix. Spread in 9x13 pan (greased). Melt 1/2 stick butter with chocolate chips. Spread over peanut butter mix. When cooled, cut into squares.