1. For the Tart dough: Cut the butter into small pieces and work it into the flour with your fingers.
2. Quickly gather the pastry with a few drops of water.
3. Press the dough into a loose-based tart tin (approx. 22 cm in diameter).
4. Cover and refrigerate for about 30 min.
5. Prick holes in the crust with a fork and pre-bake in the middle of the oven for approx. 20 min. at 200°C (fan oven).
6. For the filling: Sprinkle the cheese on the pie crust, while it is still hot.
7. Beat the eggs with the cream, salt and pepper and pour into the crust.
8. Bake the tart in the middle of the oven for approx. 25 min. at 200°C (fan oven).
9. Remove from the oven and let cool on a rack.
10. For the mushroom-onion mixture: Brown the butter in a sauté pan and sauté the onion and chanterelles over a medium heat, stirring constantly, for about 10 min.
11. Top the warm pie with the mushrooms and onions.
12. Garnish with parsley and serve with a green salad.