In a 4-quart Dutch oven combine the chocolates, half-and-half or light cream, and sugar. Bring to boiling; reduce heat. Simmer mixture, uncovered, over low heat about 2 minutes or until mixture is creamy, stirring frequently. Remove from heat; stir in the vanilla.

Pour the hot sauce into 7 or 8 hot, clean half-pint jars or 16 (4-ounce) jars, leaving a 1/2-inch headspace. Place metal lids on jars. Screw metal bands onto jars following manufacturer's directions. Store chocolate sauce in the refrigerator for up to 3 weeks. (The sauce must be stored in the refrigerator after placing in jars. Even though the hot sauce may cause the lids on the jars to seal, this is not a secure canning seal. Do not store at room temperature.) Serve sauce warm* over ice cream, eclairs, or fresh berries. Makes eight 1/2-pint or sixteen 1/2-cup jars (128, 1-tablespoon servings)

To reheat, place 1/2 cup sauce in a 1-cup glass measure. Microwave, uncovered, on 100 percent power (high) for 1-1/2 to 2 minutes or until heated through, stirring once. Or, place in a small saucepan. Cook and stir over medium heat about 5 minutes or until heated through.