Combine the milk, cream, salt, and about half of the sugar in a heavy-based saucepan that holds at least 2 quarts. Split the vanilla bean lengthwise and scrape out the seeds. Add both the seeds and the bean to the milk mixture. Bring just to a simmer over medium- high heat. Remove from the heat and let steep for 15 minutes, stirring frequently to keep a skin from forming.
Fill a large bowl with a few inches of ice water. Have ready a smaller metal bowl that will fit into the ice-water bowl, and a fine sieve. Reheat the milk mixture over medium-low heat until hot but not simmering. Meanwhile, in a medium heatproof bowl, whisk together the yolks and the remaining sugar. When the milk is hot, whisk about 1/2 cup into the yolks, and then whisk the yolk mixture back into the milk. Cook, stirring constantly with a wooden spoon, until the sauce thickens ever so slightly and passes the spoon test. The temperature should be about 175°F. Immediately strain the sauce into the waiting metal bowl and set the bowl in the ice bath. Stir occasionally until the sauce is cool. Press a piece of plastic wrap directly onto the surface of the sauce (to prevent a skin from forming), and refrigerate for up to three days.
When first combined, the sauce is too thin to coat the back of a spoon dipped into the sauce.
Once it's cooked long enough, the sauce thickens just enough to coat the back of the spoon and hold a line drawn through it with a finger.
Customizing your crème anglaise
With the addition of a single ingredient, crème anglaise takes on a new identity. In fact, from one batch of crème anglaise, you can make several new sauces. Add a little of your favorite flavor extract to taste, or try one of these combinations. The amounts given here are only guidelines; feel free to adjust them to suit your tastes.
Clockwise from top: Limon, Hazelnut-Vanilla, Raspberry-Vanilla, Espresso, Chocolatey Vanilla.
For every 1/2 cup of crème anglaise, add:
2 Tbs. puréed and strained fresh or frozen raspberries
3/4 tsp. Frangelico (or try another liqueur)
3/4 tsp. instant espresso powder dissolved in 1/4 tsp. warm water
1/2 tsp. finely grated mixed lime and lemon zest (or try other citrus zests)
Chocolatey Vanilla Sauce:
1/2 tsp. Dutch-processed cocoa
Photo: Scott Phillips