Place egg yolk, half of sugar and cornstarch in stainless steel bowl. Add one-third of milk; combine. Mixture should be smooth. Place remaining milk in saucepan; sprinkle in remaining sugar.
Do not stir. Add vanilla bean; heat to boiling. Remove from heat. Remove vanilla bean. Whisk together with egg yolk mixture. Place in saucepan; heat to boiling. Reduce heat; simmer for 2 to 3 minutes.
Remove from heat; sprinkle with small amount of sugar to prevent skin from forming. Let cool. Place in mixing bowl; beat until smooth using wire whisk. Add kirsch.
Servings: