Roll out the dough, prick it with a fork, and line a 7-inch (18 cm) springform pan. Preheat the oven to 340°F (170°C) on convection mode.

Heat milk, cream, and vanilla seeds and pods in a saucepan until simmering. Remove from heat, cover, and let infuse for 10 minutes.

In a bowl, whisk egg yolks, whole egg, and sugar until pale. Add cornflour (diluted in crème fraîche) and whisk again.

Strain the infused milk and whisk it into the egg mixture. Return to the pan and cook over low heat, stirring constantly, until thickened and smooth. Use a blender if the cream is lumpy.

Pour the thickened cream into the pastry-lined pan.

Bake for 40 minutes at 340°F (170°C). After 30 minutes, remove the flan, sprinkle brown sugar on top, and caramelize under high heat for the final few minutes.