Mushroom and Onion Quiche with Gruyère (French Quiche aux Champignons)

This tart makes a fabulous start to a meal in autumn, when wild mushrooms are in season. Use chanterelles (girolles), porcinis (cèpes) or a combination. Alternatively, you can use other wild mushrooms available locally — or, if wild mushrooms are hard to find in your area, this tart works just fine with cultivated mushrooms. For best results, make the tart as soon as possible after buying the mushrooms — or gathering them if you live near the woods… This will ensure maximum flavour.

Pâte Brisée (Savoury Pie Dough):
¼ lb unsalted butter (110 g)
1 egg yolk
1 cup + 2 Tbsp. all-purpose flour, unbleached (130 g)
1 pinch sea salt

Filling:
1 lb wild mushrooms (450 g)
1 medium onion or 2 shallots
2 tsp. butter
1 tsp. extra-virgin olive oil
2 Tbsp. fresh parsley, roughly chopped
¾ cup heavy cream (180 mL)
2 Tbsp. crème fraîche or sour cream
1 egg yolk
½ tsp. sea salt
black pepper, freshly ground

Making the Pastry:
The ingredients should be at room temperature when you begin. In a large bowl, cut the butter into small pieces. Using two knives, cut in the egg yolk, then the flour and salt. This is easily done. Simply hold the knives parallel to each other and cut in opposite directions.

When the butter is well coated with flour, go in with your hands for the final blending. Mix until the dough is no longer sticky and holds together in a ball. You may need to add a bit more flour.

Form a smooth ball and let the dough rest for a minute or two. Then pat the dough into your pie pan, taking care to ensure there are no cracks. Place in the fridge to cool for at least 10 minutes.

Pat the dough into a tart pan, a quiche pan or a pie plate. Flute the edges, using your thumbs, to create a pretty border. Refrigerate.

For the Filling:
Clean the mushrooms to remove any clinging dirt and bits of the forest. If possible, simply brush them clean using a pastry brush. However, this is often insufficient to get the mushrooms clean. The solution is to wash them gently in a bowl of lukewarm water and then spin them dry in a salad spinner. Set the mushrooms on paper towels to drain.

Peel and chop the onion or shallots. Heat the butter in a skillet and sauté the onions over medium heat until they are wilted and beginning to brown, about 10 minutes. Set aside.

Cut any large mushrooms into manageable pieces. Medium-sized mushrooms may be left whole.

Heat the olive oil to sizzling in a separate skillet. Add the mushrooms and sauté until they have given off and reabsorbed their juices. Add the chopped parsley and sauté one minute more. Add 1/4 tsp. salt and grind in some black pepper. Set aside.

Preheat the oven to 350°F (180°C/160°C fan, Gas Mark 4).

In a medium bowl, whisk together the creams and the egg yolk. Add the remaining 1¼ tsp. sea salt. Grind in some black pepper. Stir.

Assemble the tart: Spread the sautéed onions over the bottom of your tart shell. Scatter the mushrooms evenly on top of the onions. Ladle on the cream and yolk mixture.

Bake for 30-40 minutes, until the crust is a golden brown and the filling has set and is also starting to brown.

Serve hot or warm.

Makes 4-6 servings.