1 (6 oz.) pkg. semi-sweet chocolate chips or 4 (1 oz.) sq. semi-sweet chocolate
2 tbsp. butter
1 (14 oz.) can sweetened condensed milk
2 tbsp. water
1 tsp. vanilla extract

In heavy saucepan over medium heat, melt chips and butter with milk, water, and vanilla. Cook and stir constantly until thickened, about 5 minutes. Serve warm. Refrigerate leftovers.

To reheat: In small heavy saucepan, combine desired amount of sauce with small amount of water over low heat, stir constantly until heated.

Microwave: In 1 quart glass measure, combine ingredients. Cook on 100% power (high) 3 to 3 1/2 minutes, stirring after each minute.