This section is from the book "The American Woman's Cook Book", by Ruth Berolzheimer. Also available from Amazon: The Domestic Arts Edition of the American Woman's Cook Book.
3/4 cup sugar
3 eggs, separated
2 cups cream cheese
Blend butter, 1/4 cup sugar, crumbs and cinnamon. Press 3/4 of this mixture on the bottom of a 9-inch spring form pan. Soak gelatin in 1/2 cup cold water for 5 minutes. Cook egg-yolks, remaining sugar (1/2 cup) and water (1/2 cup) in a double boiler, stirring constantly, until mixture coats a metal spoon. Add gelatin and stir until dissolved. Add gradually to cream cheese, add lemon juice, rind and salt, beat thoroughly. Cool, when beginning to congeal, beat several minutes with an egg beater. Whip cream and fold in with stiffly beaten egg-whites, blend thoroughly. Pour onto crumbs. Sprinkle remaining crumbs over top. Chill until firm. Serves 10 to 12.
For variety use crumbs made from graham crackers, vanilla wafers, gingersnaps, chocolate cookies, browned dried bread crumbs, crushed cornflakes or other suitably prepared breakfast foods in place of zwieback.