2 egg yolks
2/3 c. sugar
2 tsp. hot water
2/3 c. flour
1 tsp. baking powder
1/2 tsp. vinegar
1/6 tsp. salt
2 egg whites

Beat yolks until thick. Add sugar gradually and continue beating. Add water, flour (mixed and sifted with the baking powder and salt). Fold in the stiffly beaten whites and vinegar. Bake 35 minutes in a moderate oven.