Florence Wassman'S Sponge Cake
["4 or 5 egg yolks", "1 1/2 c. sugar", "1/2 c. boiling water", "1 1/2 c. flour", "1/4 tsp. salt", "1 tsp. baking powder", "vanilla"]
["Whip egg yolks and mix all ingredients together.", "Whip and fold in egg whites.", "Pour into tube pan.", "Bake at 350\u00b0 for 1 hour to 1 hour and 15 minutes."]
["egg yolks", "sugar", "boiling water", "flour", "salt", "baking powder", "vanilla"]