1) Separate the egg yolks from the egg whites. Beat the egg whites until stiff peaks form, then add sugar and continue beating until a glossy meringue forms. Mix in the egg yolks, oil, and gently fold in the flour combined with baking powder.
2) Pour the batter onto a baking sheet lined with parchment paper and bake at 170°C until golden brown, about 20 minutes.
3) Cut the apples into small pieces, place them in a pot, pour in half the amount of water, and simmer for 5 minutes. In the remaining water, dissolve the custard mix and sugar, then pour it over the apples. Cook until thickened.
4) Pour the apple filling over the baked cake base immediately and let it cool completely.
5) Mix the cream cheese with sugar and whipped cream. Gently spread this mixture over the cooled apple filling. You can sprinkle cinnamon or chocolate on top. Chill and serve.

Enjoy your delightful treat!