3 c. heavy cream
1 c. milk
3/4 c. sugar
3/4 tsp. ground cinnamon or 2 cinnamon sticks
4 egg yolks
3 oz. semi-sweet chocolate
1 oz. unsweetened chocolate

In a large heavy saucepan, combine the cream, milk, sugar, and cinnamon. Cook over moderately high heat, stirring occasionally, until the sugar is dissolved and the mixture is hot.

In a medium bowl, whisk the egg yolks briefly. Gradually whisk in 1 cup of the hot cream mixture. Slowly whisk the egg yolk mixture into the remaining hot cream in the saucepan. Cook the custard over moderate heat, stirring constantly, until it thickens enough to coat the back of a spoon lightly, about 8 minutes. Do not let boil.

In a double boiler or heavy saucepan, melt the semi-sweet and unsweetened chocolate over low heat, stirring occasionally, until smooth. This can also be done in the microwave.

Gradually stir 2 cups of the custard into the chocolate; whisk to blend well. Stir the chocolate mixture into the remaining custard in the saucepan and blend well. Strain into a stainless steel bowl and let cool to room temperature. Pour into the canister of an ice cream maker and freeze according to the manufacturer's instructions.