This dessert is made of apples, eggs, sugar and vanilla and is slow-cooked in the oven for a moist, dense, delicious finish. Serve hot the day of, and then eat the leftovers cold. Whisk together 5 egg yolks with 1/4 cup sugar and add the seeds of 1 vanilla bean. Add the egg whites beaten into soft peaks. Peel the apples and cut them into thin slices. Add them to the mixture and pour into a buttered cake mold. Bake in a preheated oven at 200 °F for 4 hours. Every 30 minutes, moisten the cake with 1 teaspoon butter.