Apple cake with hazelnut crumble

Ingredients for 1 servings:

• 500 g apples (e.g. Boskop)
• some lemon juice
• 125 g butter, soft
• 85 g powdered sugar
• 1 packet of vanilla sugar
• 3 egg yolks
• 3 egg whites
• 1 pinch of salt
• 40 g sugar
• 60 g cornstarch
• 150 g flour
• 1 tsp, heaped baking powder
• 75 g butter
• 75 g sugar
• 100 g flour
• 50 g hazelnuts, ground
• 1 pinch of salt
• Cinnamon powder, to taste
• Fat, for the shape

Instructions

Working time approx. 30 minutes; Cooking/baking time approx. 45 minutes; Total time approx. 1 hour 15 minutes

Grease a 26 cm springform pan and line the bottom with baking paper. Peel and core the apples, then quarter or sixth them, then drizzle with a little lemon juice. Beat the butter, powdered sugar, vanilla sugar, and egg yolks until light and creamy. Beat the egg whites with a pinch of salt. Mix the sugar and cornstarch and gradually add them, beating until stiff peaks form. Fold the egg whites, flour, and baking powder into the butter mixture. Spread the mixture into the pan and scatter the apples on top. Bake in a preheated oven at 175°C (convection oven) for about 10 minutes. In the meantime, make the crumble topping. Knead the butter, sugar, flour, nuts, cinnamon, and salt into crumbles. Spread these over the cake and bake for 30-35 minutes.