2 c. peanut butter
1 c. brown sugar
1/2 c. butter, melted
1 tsp. vanilla extract
1/2 lb. confectioners sugar
2 c. chocolate chips
4 tbsp. butter

Mix first 4 ingredients until smooth. Add confectioners sugar a little at a time (you may not need it all). Spread in a buttered 9 x 13 pan. Put last 2 ingredients in a bowl and microwave until melted. Spread over peanut butter mixture. Let set, then cut into squares.