The combination of cocoa powder and unsweetened chocolate creates an ice cream with a more complex testure.Jerry refers to this as "mouthfeel". Melt the unsweetened chocolate in the top of a double boiler over hot, not boiling water. Gradually whisk in the cocoa and heat, stirring constantly, until smooth. ( the chocolate may "seize" or clump together. Don't worry, the milk will dissovle it). Whisk in the milk, a little at a time, and heat until completely blended. Remove from the heat and let cool. Whisk the eggs in a mixing bowl until light and fluffy, 1-2 minutes. Whisk in the sugar, a little at a time, then continue whisking until completely blended, about 1 minute more. Pour in the cream and vanilla and whisk to blend. Pour the chocolate mixture into the cream mixture and blend. Cover and refrigerate until cold, about 1-3 hours, depending on your refrigerator. Transfer the mixture to an ice cream maker and freeze according to manufacturer's instructions. Variation: Chocolate Chocolate chip: Add 3/4 cup semisweet chocolate chips after the ice cream stiffens, about 2 minutes before it is done, then continue freezing until the ice cream is ready. The rick fully textured ice cream is a chocoholic's delight. Some of Ben and Jerry's friends take it a step further and serve it with hot fudge sauce!