In a mixing bowl, combine 2 egg whites and a pinch of salt.

Begin whipping the egg whites until they become frothy.

Gradually add 130 g sugar and 5 g vanilla sugar while continuing to whip.

Add a pinch of citric acid (or 1 tsp lemon juice) and 8 g cornstarch.

Whip until stiff peaks form and the mixture is glossy.

Preheat your oven to 90°C (194°F).

Pipe or spoon the meringue mixture onto a baking sheet lined with parchment paper.

Bake for about 80-90 minutes, or until the meringues are dry and can be easily lifted from the parchment paper.

Let the meringues cool completely on the baking sheet.

In a saucepan, combine 2 egg yolks, 50 g sugar, and 30 g cornstarch.

Gradually add 300 ml milk, whisking constantly to avoid lumps.

Place the saucepan over medium heat and bring the mixture to a boil, stirring constantly.

Continue to stir and cook until the mixture thickens to a custard-like consistency.

Remove from heat and add 30 g butter, 50 g mascarpone, and 10 g vanilla sugar.

Stir until the butter and mascarpone are fully melted and the mixture is smooth.

Allow the cream filling to cool down to room temperature.