1. In a heavy small saucepan, combine 1 cup of the whipping cream, the milk chocolate, and 3 tablespoons of the sugar. Cook and stir over medium heat about 5 minutes or until mixture comes to a full boil and thickens. (If chocolate flecks remain, use a wire whisk to beat mixture until smooth.)
2. In a medium bowl, beat 2 of the egg yolks with a wire whisk. Gradually stir all of the hot mixture into the beaten egg yolks; stir in 1/2 teaspoon of the vanilla. If using glass serving containers, cool slightly. Divide chocolate mixture evenly among 8 small glasses, dishes, pot de crème cups, or ramekins. Cover and refrigerate for 2 hours.*
3. Make the second layer of dessert using the same method with the remaining 1 cup whipping cream, the dark chocolate, the remaining 3 tablespoons sugar, the remaining 2 egg yolks, and the remaining 1/2 teaspoon vanilla. Divide dark chocolate mixture among chilled glasses. Cover and refrigerate about 4 hours or until firm.
4. Makes: 8 servings
5. *Note: To have the darker layer on the bottom, make the layer from Step 3 first and follow with the layer in steps 1 and 2.