1 3/4 cups heavy cream
3/4 cup 1- or 2-percent milk
1/2 cup granulated sugar, divided
1/4 teaspoon kosher salt
1 vanilla bean
5 large egg yolks

In a heavy, nonreactive saucepan, stir together the cream, milk, 1/4 cup of the sugar and the salt. Split the vanilla bean lengthwise and use a knife to scrape seeds carefully from pod. Add seeds and split pod to pan over medium-high heat. When mixture just begins to bubble around edges, remove from heat, cover pan and let steep for about 30 minutes.

In a medium, heatproof bowl, whisk the egg yolks just to break them up, then whisk in remaining sugar until smooth. Set aside.

Uncover cream mixture and return pan to medium-high heat. When mixture approaches a bare simmer, reduce heat to medium. Carefully scoop out about 1/2 cup hot cream mixture and, whisking eggs continuously, add cream to bowl with egg yolks. Repeat, adding another 1/2 cup hot cream to bowl with egg yolks. Using a heatproof, rubber spatula, stir cream in saucepan as you slowly pour egg-and-cream mixture from bowl into pan.

Cook mixture carefully over medium heat, stirring continuously, until thickened, coats back of a spatula or wooden spoon and holds a clear path when you run your finger along spatula or spoon, for 1 to 2 minutes.

Strain through a fine-mesh strainer into a clean container. Set container in an ice-water bath, wash spatula and stir occasionally until mixture is cool. Remove from ice-water bath, cover with plastic wrap and refrigerate for a least 2 hours or overnight to use as a sauce over cake or fresh fruit. Or portion into individual servings and freeze for several hours for a semifreddo.