2/3 cup white sugar
1/3 cup unsweetened cocoa powder
3 egg yolks, beaten
2 2/3 cups heavy cream
1/3 cup semisweet chocolate chips
In large bowl, stir together sugar and cocoa. Add egg yolks and blend with electric mixer. Add cream a little at a time, beating well after each addition. Chill mixture in refrigerator.
While cream mixture is chilling, grate chocolate chips in blender or food processor or using a rotary grater, until fine. Stir into cream mixture. Freeze in canister of ice cream maker according to manufacturer's instructions.