Peel the rhubarb stalks and cut them into slices or cubes. Mixed them with 100g of sugar and let it macerate for at least 1 hour.
Unroll the pie crust and precisely fit it in a tart pan (9 or 11 inches). Poke the dough all over with a fork. Then put the pie in the fridge.
Preheat the oven to 390F.
Drain the rhubarb in a colander.
In a pan, put the butter and lightly cook the rhubarb, stirring from time to time (must stay tender, do not overcook).
Remove from the heat and add the rest of the sugar (50 g).
In a bowl, mix the egg, cream, and extract vanilla.
Put the rhubarb evenly on the sweet dough, pour the mixed cream egg on it.
Cook in the oven during 25-30 min.
Before serving, sprinkle powder sugar on the pie if you want.
This pie can be eaten lukewarm or cold.