Espresso Sauce

Directions

1. 1
   Pour the milk and heavy cream into a heavy-bottomed pot. On a cutting board, split the vanilla bean down the middle and, using the top of your knife, scrape all the seeds into the milk. Add the bean pod to the milk and bring the milk gently to a boil over medium heat, being careful not to scorch the milk or allow it to boil over. Lower the heat and simmer for 10 minutes, uncovered. Remove from the heat and allow the vanilla bean to steep in the milk for another 5 minutes.
2. 2
   Meanwhile, in the bowl of an electric mixer, whip the egg yolks and sugar together at medium speed for 5 minutes. Remove the vanilla bean from the milk, then stir several tablespoons of the hot milk into the egg yolk-sugar mixture to temper the eggs.
3. 3
   Fill a large bowl halfway with ice water. Return the pot of milk to the stove and, over low heat, add the egg yolk-sugar mixture in a slow, steady stream, stirring it in with a wooden spoon. Stir the coffee into the sauce with a wooden spoon and continue to cook for 7 to 8 minutes, stirring constantly, until the custard has thickened and coats the back of the spoon. Remove from the heat and cool completely by setting the bottom of the pot in ice water and stirring to release heat. Once cool, the sauce can be covered and refrigerated for up to 24 hours.