Mushrooms are standard fare in tarts and quiches but rarely do they add as much to a dish as they do to this one. Too many recipes rely on undercooked button mushrooms floating on top of goopy eggs. I can virtually hear the posh accent of Mary Berry, of The Great British Baking Show fame, chiding the baker and poking said quiche with an upside-down fork: "the mushrooms are too full of moisture. It has a soggy bottom." This tart is different. The mushrooms are rich and the flavors are folded into the filling. The earthiness is layered by combining multiple mushroom species.
First introduced to me as 'Uncle Bill's Mushroom Tart' by my neighbor Cora, I was informed that it was the benchmark of a delicious mushroom recipe. That it was the one tart to rule them all. Although I was skeptical at first, it wasn't long until I became a true believer in Uncle Bill, and concluded that whomever and wherever he was he had stumbled onto something magical.
Most mushroom species have the dual qualities of being both extraordinary tonics for the immune system and sources for vegetarian umami when they're cooked. This tart's herbaceous and buttery filling elevates the flavor of a range of mushrooms, but the combination of fresh oyster mushrooms or maitake underpinned with dried porcini is hard to beat.
If you can't find oyster mushrooms in your grocery store you can quickly grow your own with a grow kit. The word porcini refers to a wide range of edible Boletus mushrooms that can be found at most grocery stores but the best stuff, like North Spore's dried porcini, is wild Boletus edulis that comes from our native temperate forests.
Recipe adapted from Uncle Bill's Mushroom Tart: the original recipe calls for beef stock instead of vegetable / mushroom stock. We added a pinch of thyme too. Substitute fresh Black Kings, King Trumpet, Golden Oysters, or Pink Oysters for the blue oysters or maitake should those not be available. The tart crust recipe is adapted from Klancy Miller's tart recipe where she makes two crusts, one for now and one to be stored in the freezer for later (an excellent idea in our opinion!)
1oz (28g packet) dried porcini mushrooms
1 generous cup chopped fresh blue oyster mushrooms, maitake (hen of the woods), or 50/50 blend of both
1 medium red onion
15 sprigs of parsley, leaves only
2 tsp dried thyme
1/4 cup extra virgin olive oil
2 Tbs salted butter
1 Tbs tomato paste
1 cup lukewarm vegetable or mushroom stock
3 large eggs
1/2 cup freshly grated Parmigiano-Reggiano
salt and pepper to taste
Crust: (makes two crusts - save one in your freezer for another tart!)
2 1/3 cups all-purpose flour plus more for dusting
1 tsp kosher salt
2 sticks of butter, cut into small cubes and chilled
1/4 to 3/4 cups of ice water
1. Soak dried porcini in warm water for at least 1/2 hour.
2. Make your tart dough. In a large bowl, mix together the flour and salt. Add the small pieces of butter by hand and mix it together. Rub the butter into the flour and roll it into small pea-sized pieces. Continue this process until the butter is fully incorporated into the flour and the mixture reaches a consistency like course ground cornmeal with a touch of moisture.
3. Add the ice water one spoonful at a time and stir the mixture by hand. You are shooting for a dough that isn't too wet, but has just barely pulled all the buttery flour into one mass. Shape the mass into a ball by kneading it one or two times.
4. Take one half the dough, flatten it, wrap it in plastic and store it in the freezer for up to one month. Store the second half in the fridge until your tart filling is complete.
5. Finely chop the onion and parsley. Heat the olive oil and butter in a heavy sauce pan and add the chopped ingredients and dried thyme. Gently sauté the onion and parsley for 10 minutes on medium-low heat. Drain and coarsely chop the porcini. Add the porcini mushrooms, the chopped oysters or maitake, and tomato paste to the pan and sauté for another 5 minutes.
6. Pre-heat your oven to 375°
7. Add the vegetable or mushroom stock and season with salt and pepper. Cook slowly until all the broth has evaporated (about 35 minutes). Remove the pan from heat and transfer mixture to a bowl to cool.
8. Remove your prepared tart dough from the fridge and roll it out onto a floured surface.
9. Line dough in a 4.5 x 14 inch tart pan or a 9-inch pie dish (preferably with a removable bottom). Cover the outer crust with aluminum foil and add cooking weights or dry beans to the interior and bake for 10 minutes. Keep an eye on it and make sure it doesn't burn! A wandering attention span has ruined many a tart shell. The crust should be tan but not dark brown. Remove it from the oven and allow it to cool.
10. Add eggs and Parmigiano to the cooled filling in the bowl. Mix well and pour into the cooled pastry shell and bake for another 20 minutes or until the eggs are cooked through. Cool in the pan for 10 minutes before removing.
Serve immediately. This tart goes great with a fresh spring salad like the shaved fennel and arugula salad with a yogurt and horseradish dressing pictured below.