For the crust: Place the Frosted Flakes in a large bowl and gently crush them. Do not turn them into crumbs!

Melt the butter and add it to the cereal.

Line a loaf pan with parchment paper and press the cereal mixture into the bottom and up the sides to form a crust. Chill in the refrigerator for 30 minutes.

For the chocolate mousse: Heat the milk until hot.

Break the chocolate into pieces and pour the hot milk over it. Stir until the chocolate is completely melted.

Set aside about 10 hazelnuts from the chocolate and reserve them.

Add the sugar and egg yolk to the melted chocolate and mix well.

Beat the egg whites with a pinch of salt until stiff peaks form.

Gently fold 1/4 of the beaten egg whites into the chocolate mixture to lighten it, then carefully fold in the remaining egg whites without deflating them.

Spread the mousse over the prepared crust.

Using a mortar and pestle, roughly crush the reserved hazelnuts and sprinkle them over the tart. Chill for at least 2 hours to allow the mousse to set. Enjoy!