Crumble
150g flour
2 tablespoons sugar
100g cold butter

Filling
3 apples
2 tablespoons freshly squeezed lemon juice
1 teaspoon grated lemon zest
2 tablespoons sugar
50g hazelnuts

Vanilla sauce
50g milk
50g heavy cream
1 egg yolk
2–3 teaspoons vanilla sugar

In a bowl, mix the flour with 2 tablespoons of sugar. Add grated or sliced butter and knead, making the crumble. Grease the baking pan with butter. Core the apples and peel if necessary, slice, splash with lemon juice, stir, place in the baking pan. Zest the lemon and mix the zest with 2 tablespoons of sugar, sprinkle over the apples. Chop the hazelnuts and sprinkle them over the apples. Top everything with crumble and bake at 220 C for 20–25 minutes until golden brown. Make the vanilla sauce by bringing milk and heavy cream (you can use either one or the other, or both) to a boil. Set aside. In a separate dish, mix the egg yolk with vanilla sugar and add to the warm milk or cream. Bring to a boil, slowly stirring until thicker. Serve hot or cold.