To scalded milk, add the vanilla and noncaloric sweetener.
Beat egg yolks until thick and lemon-colored.
Stir in milk.
Set five 6-ounce custard cups in shallow pan on oven rack and fill them with custard.
Pour hot water around cups, 1 inch deep.
Bake in slow oven (325°) about 45 minutes, or till knife inserted off-center comes out clean.