12 oz. pkg. semi-sweet chocolate baking pieces
12 oz. pkg. milk chocolate baking pieces
1 tbsp. butter
1 can sweetened condensed milk
1 tsp. vanilla
4 drops oil or peppermint or 1 tsp. peppermint extract

Melt chips and butter in top of double boiler. Remove from heat and add remaining ingredients. Stir well and pour into buttered 9 x 13 inch pan. Cool and cut into small squares.