Prepare 3 round 9 – 10 in (18 – 20 cm) baking pans with parchment paper on the bottom and sides of baking pans; grease and flour them.
Whip egg yolks with half of the sugar (1/2 cup) until they are thick, light in color and double in volume. Set aside.
Whip egg whites with cream of tartar until foamy, add remaining sugar and continue whipping until whites are thick, as for meringue. Fold whites into yolk mixture and mix well.
Divide mixture and pour into prepared baking pans. Bake in preheated oven to 350°F (180°C) for approximately 15 minutes or until tester comes out clean. Once cakes are taken from the oven they will deflate a little. If they are removed from the oven before they are done they will deflate even more. Cool, invert cakes onto a platter and remove parchment paper.
If 3 round baking pans are not available use 2 and divide them horizontally in 2 layers when they are cool.
Prepare Chantilly cream: Whip heavy cream until it starts to thicken. Add confectioner´s sugar and continue beating until very thick. Stir in cherimoya pieces and mix.
Place one cake on a serving dish and cover with butterscotch. Place second cake on top and cover with chantilly cream with cherimoya. Top with third cake and chantilly and cherimoya mixture if there is some left. Sprinkle slivered almonds on top for decoration.
Pour butterscotch sauce on top making designs and serve remaining sauce in a sauceboat.
Melt sugar in a saucepan over low heat until caramel color. Remove from heat and carefully stir in milk.
Mixture will bubble. Continue stirring, return to medium heat until sauce thickens lightly.
Variation: Dulce de leche or chocolate fudge may be used instead of butterscotch.