Notes: This rich, smooth sauce can be made up to 2 days ahead and kept covered and chilled. Our favorite liqueurs for this recipe include Kahlúa, Frangelico, and Drambuie.
With a sharp paring knife, cut vanilla bean in half lengthwise. With the tip of a sharp knife, scrape out vanilla seeds into a small saucepan.
Add bean halves and milk to saucepan and bring to a simmer over medium heat. Remove from heat and let mixture sit 15 minutes. Discard vanilla bean halves.
Whisk egg yolks, sugar, and cornstarch into milk and bring to a boil over high heat, whisking constantly, until mixture boils and thickens slightly, about 3 minutes. Immediately pour mixture into a bowl and let cool, stirring occasionally, to room temperature. For extra fun, try adding up to 2 tbsp. brandy or liqueur to the bowl as cream cools.
Note: Nutritional analysis is per tablespoon.