In a mixing bowl, beat together the eggs, granulated sugar, and vanilla sugar until frothy.

Gently fold in the sunflower oil and melted butter until combined.

Sift in the flour and baking powder, mixing until just incorporated.

Line a springform pan with parchment paper and fill it with the dough.

Place the pan in the freezer for 20 minutes to firm up the base.

Meanwhile, heat the milk with the vanilla sugar in a saucepan until it reaches near boiling.

In a separate bowl, whisk together the egg yolk, granulated sugar, and cornstarch until smooth.

Gradually pour the hot milk into the egg mixture while whisking, then return to the saucepan and cook over medium heat until the mixture thickens.

Allow the mixture to cool completely, then fold in the whipped cream and diced peaches gently.

Preheat the oven to 180°C (350°F).

Pour the cream and peach mixture over the chilled cake base in the springform pan, then sprinkle with sliced almonds.

Bake in the preheated oven for 25 minutes, or until golden brown on top.

Once done, let it cool, unmold the cake from the pan, and dust with powdered sugar before serving.