Melt the chocolate in the top of a double boiler, stirring occasionally, being careful not to scorch the bottom.
Combine the egg yolks and the sugar and whip to a creamy and smooth yellow.
Combine the milk, cream and vanilla bean in a pot over medium heat and bring to a boil.
Temper the eggsugar combination by whisking into the egg mixture 1/3 of the hot milk. Stir this in to temper the eggs before adding them to the remainder of the milk. Using a whip to whisk the milk, pour the tempered eggs into the hot milk, and cook the milk and egg mixture together. Stir with a wooden spoon until the mixture thickens enough to coat the back of a wooden spoon.
Add the melted chocolate to the hot milkegg mixture by whipping in with a wire whisk.
Strain the mixture through a fine mesh strainer and cool quickly in an ice bath before refrigerating the mixture. Chill the ice cream base for several hours before continuing onto the ice cream making. Freeze the mixture in an ice cream freezer according to the manufactures directions.