Mushroom Tart
Adapted from The Smitten Kitchen Cookbook by Deb Perelman

I tweaked a few things from Deb’s recipe in the book. I increased the butter in the filling to 2 tablespoons because after I used 3/4 of the stick for the tart crust, using just 1 tablespoon of butter and leaving the remaining tablespoon behind, seemed cruel, almost. I couldn’t get my hands on any wild mushrooms (much as I adore them) and I used the creminis that my local Trader Joe’s stocked – worked out beautifully. I added the wine at the end of cooking the mushrooms because I really love the way white wine infuses mushrooms at the end of cooking. And instead of the Fontina cheese, I used Gruyere instead as I happen to prefer its punch especially with mushrooms. Last, but not least, I wanted to have a tiny bit more egg, but not so much so as to add another egg into the mix, so instead of large eggs, I swapped in the extra-large ones. If you only have large eggs, fear not, that’s how Deb’s recipe was originally written. And if you’re a huge Ina Garten devotee and buys only extra-large eggs, this will work too – hooray!

A technical note – I found that the crust behaved a lot better when I baked it with pie weights though Deb says it’ll bake fine without, mine shrunk a tiny bit and I find that an ounce of prevention, especially the kind that is super easy, goes a long way for me. After all, tart dough, while not the hardest thing to make, isn’t a 5 minute proposition.

For the Crust:
1 cup plus 2 tablespoons (140 grams) all-purpose flour
1/4 cup (30 grams) yellow cornmeal
1/2 teaspoon kosher salt
6 tablespoons (85 grams or 3/4 stick) unsalted butter, chilled, diced, plus additional to grease the foil
1 large egg

For the Filling:
2 tablespoons unsalted butter
1 tablespoon olive oil
2 medium shallots, thinly sliced
1 garlic clove, minced
1 1/2 pounds (680 grams) assorted wild mushrooms and cremini, or cremini alone if wild mushrooms can’t be found
1 teaspoon fresh thyme leaves
1/4 cup (60 ml) dry white wine
Kosher salt (I used about 1 teaspoon)
Freshly ground black pepper
1/4 cup (60 grams) mascarpone cheese, room temperature
1/4 cup (60 ml) whole milk
2 extra large eggs
1/2 cup (55 grams) grated Gruyere cheese
1/4 cup (25 grams) finely grated Parmigiano-Reggiano or Pecorino Romano cheese

Make the Crust:
1. Combine the flour, cornmeal, and salt, in the work bowl of your food processor fitted with a blade, and pulse a few times to distribute the ingredients evenly. Add the butter, and pulse the machine until the butter is in small bits, the size of peas. Add the egg, and run the machine until the dough starts to clump together in large chunks.

2. On a lightly floured sheet of plastic wrap (I find that I have to get 2 sheets and overlay them with one another) shape your dough into a ball and flatten into a circular disk. Cover with another (or 2) piece of the plastic wrap and using a rolling pin, roll the dough out to a 12-inch circle. [I prefer to use plastic wrap for tart dough because the chances of the dough breaking on your before you transport it to the tart pan, are very low.] Once the dough has been rolled to correct size, peel off the top piece of the plastic wrap. Gently lift and invert the dough (and bottom piece of plastic wrap) over a 9-inch fluted, removable bottom tart pan. You can use the plastic and your fingers underneath to gently position the dough exactly where you want it. Carefully peel back the remaining piece of plastic, and press thee dough against the bottom and sides. Run your rolling pin firmly over the top edge of your pasty pan to remove the excess dough. Transfer the tart pan onto a baking sheet and place in the freezer for 20 to 30 minutes.

3. Heat your oven to 375 degrees F (click here for Celsius/gas mark). Lightly butter one side of a 12-inch square piece of foil, and press the foil, butter side down, firmly against the base and sides of the crust. Place the pie weights (or beans or pennies) on top, transfer the tart pan onto a shallow baking sheet, and bake for 10 minutes. Carefully remove the weights and the foil, and bake for another 5 to 8 minutes, or until the crust is firm and lightly golden at the edges. Transfer the tart shell to a cooling rack until needed. Reduce the oven temperature to 350 degrees F.

Make the Filling:
4. In a large sauté pan set over medium heat add the butter and the oil until the foaming subside. Add the shallots, and cook, stirring from time to time until they are soft, about 2 to 3 minutes. Add the garlic and cook, stirring, another minute. Raise the heat to medium-high and add the mushrooms and the thyme. The mushrooms must fit in a single layer on your pan; if they do not, you will need to cook them in batches. Cook the mushrooms until they are tender and the liquid they release has completely evaporated (i.e. the pan is nearly dry), about 9 to 10 minutes. Add the wine and deglaze, scraping the brown bits (a fond) off the bottom of the pan with a wooden spoon, until the pan is dry. Season the mushrooms to taste with salt and pepper and transfer to a plate to cool.

5. In a large bowl combine the mascarpone with the milk and whisk together until smooth. Whisk in the eggs, and stir in the Gruyere and the Parmigiano-Reggiano. Fold in the mushrooms.

Assemble the Tart:
6. Pour the filling into the tart shell and bake for about 35 to 40 minutes, or until the tart is puffed and golden on top, and the tip of a knife inserted into the center and turned releases no wet custard. Transfer the tart to a cooling rack and cool for 10 minutes before serving. The tart is best served warm but is also delicious at room temperature. Serve it with your favorite green salad, such as this one, for a lunch that will make you feel like you’ve just been transported to France.

Serves 6 to 8 (makes one 9-inch round tart)