Surprise Angel Cake

My daughter's favorite, will easily serve 10 to 12 little children
1 cup cake flour
3/4 cup sugar
3 1/2 cup egg whites (12 eggs*)
1 1/2 teaspoons cream of tarter
1/4 teaspoon salt
1 1/2 teaspoons vanilla
3/4 cup sugar
Sift four with 3/4 cups sugar four times. Beat egg whites, cream of tarter, salt and vanilla to soft peaks. Add 3/4 cups sugar to egg whites in small amounts, beating after each addition. Sift 1/4 dry mixture to egg whites and fold in, until all dry ingredients are mixed in. Bake in ungreased 10 inch tube pan in 3750F oven for 35 to 40 minutes. Cool on wire rack. With serrated knife, cut 1 inch from top of cake. Cut out a trench 2 inches wide and deep.
Fill trench with filling, replace top 1 inch piece and ice.
Fill cake with custard using the egg yokes instead of whipped cream.
Filling
1 cup heavy whipping cream
3 tablespoons sugar
1/2 teaspoon vanilla
1/2 cup cherries, quartered
1/2 cup crushed pineapple, drained
1/2 cup tiny marshmallows
Make thick whipped cream and fold in sugar, vanilla, fruit and marshmallows.
Icing
Seven Minute Frosting
1 1/2 cups sugar
1/2 cup water2 egg whites
1/4 teaspoon cream of tartar
1 teaspoon vanilla
In top of double boiler, combine sugar, water, egg whites and cream of tartar. Beat with electric mixer on low speed for 30 seconds. Place over boiling water and cook, beating constantly on high speed for seven minutes or until stiff peaks form. Remove from heat; add vanilla. Beat 2 to 3 minutes more until frosting reaches spreadable consistancy.
Frost cake and chill until serving time.