From the blog For Love of the Table
2 c. milk
1 c. coffee beans
2 c. cold heavy cream
8 egg yolks
1 c. sugar
pinch of salt
1/2 T. pure vanilla extract
4 t. very finely ground coffee beans (espresso grind)
Place the milk in a small saucepan. Add the coffee beans to the pan. Bring to a simmer. Remove from the heat, cover and let steep for 1 hour. While the milk is infusing, pour the heavy cream into a large bowl and refrigerate.
Strain the milk into a clean saucepan (discard the coffee beans), add half of the sugar and return the pan to high heat. Place the egg yolks in a large bowl with the remaining sugar and salt and whisk until thick and pale yellow. Take the bowl of chilled cream out of the refrigerator and place a strainer over the bowl; set aside near the stove.
When the milk boils, temper the egg yolks by gradually whisking in about a cup of the hot milk. Stir the tempered egg mixture back into the saucepan and place the pan over medium heat. Cook, stirring constantly with a heat-proof spatula, until the custard is thickened. (If you dip a spoon in the custard and draw your finger across the back of the spoon, a path will remain. Also, an instant read thermometer will read about 170°. The custard must be cooked beyond 160°, but must not go over 180°.) Immediately strain the custard into the bowl of cold cream. Stir in the vanilla. Place the bowl of custard in a larger bowl of ice water and let cool, stirring occasionally. Cover and refrigerate until deeply chilled.
When ready to freeze the ice cream, whisk in the espresso. Freeze the ice cream in an ice cream machine according to the manufacturer’s instructions. Transfer to a freezer container and freeze for an hour or two—or preferably overnight—before serving. Makes about 1 quart ice cream.
(Recipe inspired from The Perfect Scoop by David Lebovitz)
http://www.forloveofthetable.com/2013/10/marbled-chocolate-sweet-potato-cake.html