Bourbon Sauce

1 1/2 cups milk
1/3 cup sugar
4 egg yolks
2 tablespoons bourbon
1 teaspoon vanilla extract

In a medium nonreactive saucepan, combine the milk and sugar. Bring to a
boil over moderate heat.

Beat the egg yolks in a small bowl until liquified. When the milk boils,
gradually whisk 1/3 of it into the yolks. Return the remaining milk to a
boil over low heat and whisk in the yolk mixture. Cook, whisking constantly,
until the sauce thickens, 1 to 1 1/2 minutes; do not let boil. Immediately
remove from the heat.

Whisk the sauce constantly for 1 minute to cool. Strain through a fine
sieve into a bowl and whisk for 30 seconds. Stir in the bourbon and the
vanilla. Serve warm.