2 cups heavy cream
2 tablespoons Kahlua
2 tablespoons instant coffee
1 teaspoon vanilla extract
3 egg yolks
1/2 cup sugar
Bring the first 4 ingredients to a boil in a medium saucepan over low heat. Remove from heat and cover the pan. Let it steep for 15 minutes.
Whisk the egg yolks and sugar to blend in a medium bowl. Slowly whisk in the cream mixture. Return custard to the same saucepan. Cook over low heat until the custard thickens and leaves a path on the back of a spoon when finger is drawn across. Strain the custard in a bowl. Cover and chill. This sauce will not keep for more then a few days.