Via Dorie Greenspan: Baking from my Home to Yours
160 g (1 cup) bittersweet chocolate
300 ml (1 1/2 cups) heavy cream
200 ml (1 cup) whole milk
4 egg yolks
70 g (1/3 cup) sugar
Bring 150 ml (3/4 cup) of the cream to boil.
Pour the cream over the chocolate and let it sit a minute.
Then stir the cream into the chocolate.
When the ganache is smooth, set it aside.
Bring the remainig cream and the milk to boil in a saucepan.
Meanwhile, in a bowl, whisk the yolks and the sugar together until just slightly thickened.
Still whisking, drizzle one third of the hot liquide into the yolks.
Slowly pour in the remaining liquid.
Pour the custard back into the pan and cook until the custard reach 170°F (76°C) on an instant-read thermometer.
Immediately remove the pan from the heat and stir the custard into the ganache.
Refrigerate the custard until chilled before churning it into ice cream.
Scrape the custard into the bowl of an ice cream maker and churn according to the manufacturer’s instructions.
Pack the ice cream into container and freeze it for a least 1 hour, until is firm enough to scoop.