6 (1 ounce) squares unsweetened chocolate
2 tablespoons butter
2 cups granulated sugar
1/4 cup light corn syrup
3/4 cup half-and-half
2 eggs
2 teaspoons vanilla extract
1 1/2 cups half-and-half
2 cups whipping cream

In a heavy medium saucepan, melt chocolate and butter over low heat, stirring often. Stir in sugar, corn syrup and the 3/4 cup half-and-half. Stir over medium-low heat until mixture comes to a boil. Simmer 4 minutes without stirring; set aside.

In a small bowl, beat eggs until blended. Stir in the 1/2 cup hot chocolate mixture. Cook and stir over medium heat until slightly thickened, about 1 minute. Cool to lukewarm.

Stir in vanilla extract, the 1 1/2 cups half-and-half and whipping cream. Pour into ice cream canister. Freeze in ice cream maker according to manufacturers directions.