DirectionsHeat the milk and vanilla bean, if using, in a medium saucepan until it bubbles form around the edges.
Remove from the heat and let stand for 10 minutes.
Using the tip of a knife, scrape half of the seeds from the bean into the milk.
Rinse the vanilla bean and save for another use.
Beat the yolks and sugar in a heatproof bowl.
Gradually whisk in the hot milk.
Rinse and dry the saucepan, and return the milk mixture to the pan.
Cook over medium-low heat, stirring constantly with a wooden spoon, until the custard is thick enough to coat the spoon (an instant-read thermometer will read 185F (85C)).
Do not boil.
Strain through a sieve into a bowl.
If not using the vanilla bean, stir in the vanilla extract.
To serve warm, use immediately.
Or place plastic wrap directly on the surface, pierce a few holes in the wrap, and let cool.
Variation: Citrus Creme Anglaise Add the grated zest of 1 lemon or orange to the strained custard.