Combine yolks, flour, butter, and milk. Stir until well mixed.
Whisk egg white in bowl then whisk vanilla extract and 1/3 Splenda. Using hand held mixer with whisk attachment.
Add yolk mixture into egg white mixture.
350F bake in the bottom oven with water plate. 60mins.
6 cupcakes, each contains 50 calories; 6 g carbs. 3 g protein.