Serves: Makes 2½ cups
- 1 cup (8 ounces) whole milk
- 1 cup (8 ounces) heavy whipping cream
- ¼ cup (1¾ ounces) sugar
- 1 vanilla bean or 2 teaspoons pure vanilla extract
- 5 large egg yolks
Fill the large bowl halfway with ice and water and set it aside. Combine the milk, cream, and sugar in the medium saucepan and warm over medium heat, stirring occasionally, until the sugar is dissolved. (If you are using vanilla extract, proceed to Step 2.) Use the tip of a paring knife to cut the vanilla bean in half lengthwise. Turn the knife over and use the dull side to scrape out the seeds, and add both the seeds and the pod to the saucepan. Heat until the mixture just begins to simmer. Remove from the heat and let steep for 30 minutes, or until you like the flavor.
Heat the milk mixture to just below the boiling point. Remove the pan from the heat. In the small bowl, whisk the egg yolks together. Slowly pour about 1 cup of the hot milk into the yolk mixture, whisking constantly, to temper the yolks. Slowly pour the yolk mixture back into the hot milk in the saucepan, whisking all the while. Return to medium-low heat and cook, stirring constantly with the spatula, until the custard thickens and registers 178° to 180°F on the thermometer.
Immediately strain the custard sauce through the strainer set over the medium bowl to remove any tiny bits of scrambled egg. (Save the vanilla bean: Rinse it thoroughly, allow to dry, then use it to make vanilla sugar) If you're using vanilla extract instead of the vanilla bean, add it now and whisk to blend. Press a piece of plastic wrap directly on the surface of the sauce then set the bowl into the bowl of ice water. Once the custard sauce has completely cooled, use or store in the refrigerator until needed.
Storing: Keep the custard sauce for up to 5 days from the day it was made, refrigerated in an airtight container with a piece of plastic wrap pressed directly on the surface to prevent a skin from forming.