In a medium saucepan, bring half-and-half, sugar, vanilla bean, and vanilla extract to a boil over medium-high heat, whisking frequently. Reduce heat to medium.

Using a ladle, add about 1 cup hot half-and-half mixture to egg yolks, whisking constantly.

Pour yolk mixture into remaining half-and-half mixture in saucepan. Cook, stirring constantly with a rubber spatula, until mixture is thick enough to coat the back of a wooden spoon and a candy thermometer registers 170°.

Remove from heat, and strain into a container set in an ice bath. Let cool completely, whisking frequently.

Add Calvados, whisking to combine. Store in an airtight container in refrigerator for up to 3 days.