Mushroom, Shallot, and Gruyère Quiche

So we had the quiche last night for dinner, and I'd have to say it was an unqualified success. Good flavors and a nice crust... no curdling of the custard... and no holes in the crust for the custard to leak out of. This "deep dish" quiche was fairly time consuming, but no more so than one made in a pie plate, and the results were significantly superior. Anna and I cobbled this together from a multiple sources... it's Cook's Illustrated (sub required) for the dough and filling... Epicurious for the garnish (i.e. non-custard stuff that goes in the filling)... and Thomas Keller/Ruhlman for general instruction and tips. Unfortunately, for anybody without a 9" ring mold (most people I'd guess), you're on your own... Ruhlman suggest putting parchment paper in a 9" cake pan, and the linked (but not free, though also in the July 2010 issue) recipe in Cook's Illustrated has instructions for a foil sling in said cake pan that might work a little better than parchment. Personally, I don't see why you can't just leave the quiche in there... but I guess that's not as aesthetically pleasing or something. Anyway, here's the recipe we worked out:

Pastry Dough

• 8 and 3/4 ounces unbleached all-purpose flour (1 and 3/4 cups), plus more for work surface
• 1 teaspoon kosher salt
• 12 tablespoons unsalted butter (1 1/2 sticks), cold, cut into 1/2-inch cubes and frozen 10 minutes
• 3 tablespoons sour cream
• 1/4-1/3 cup ice water
• 1 large egg white , lightly beaten

No, I have no idea what the deal is with the sour cream... one of Cook's Illustrated's super secret ingredients one presumes, but its presence wasn't explained in this particular recipe. I didn't notice it's presence one way or the other in the finished product.

1. Process flour and salt together in food processor until combined, about 3 seconds. Add butter and pulse until butter is size of large peas, about ten 1-second pulses
2. Mix sour cream and ¼ cup ice water in small bowl until combined. Add half sour cream mixture to flour mixture; pulse for three 1-second pulses. Repeat with remaining sour cream mixture. Pinch dough with fingers; if dough is floury, dry, and does not hold together, add 1 to 2 tablespoons ice water and process until dough forms large clumps and no dry flour remains, three to five 1-second pulses.
3. Turn dough out onto work surface and flatten into 6-inch disk; cover disk in plastic wrap and refrigerate until firm but not hard, 1 to 2 hours, before rolling. (Dough can be refrigerated for up to 24 hours. Let thoroughly chilled dough stand at room temperature 15 minutes before rolling.)
4. Lightly oil ring mold with cooking spray. Place ring mold on baking sheet lined with parchment paper. Roll out disk of dough on generously floured work surface to 15-inch circle (about 1/4 inch thick). Roll dough loosely around rolling pin and unroll into ring mold. Working around circumference, ease dough into pan by gently lifting edge of dough with 1 hand while pressing into pan bottom with other. Make sure you have plenty of overhang, to help keep the crust from falling, but trim some excess to save for hole patching. Patch any cracks or holes with dough scraps as needed. Refrigerate any remaining dough scraps. Refrigerate dough-lined pan until firm, about 30 minutes, and then freeze for 20 minutes. [Note that I just stuck it directly into the freezer for 30-45 minutes and noticed no ill effects]
5. Adjust oven rack to lower-middle position and heat oven to 375 degrees. Line dough with parchment or foil and fill completely with pie weights or dried beans (or loose change!), gently pressing weights into corners of shell. Bake on rimmed baking sheet until exposed edges of dough are beginning to brown but bottom is still light in color, 30 to 40 minutes. Carefully remove parchment and pie weights. If any new holes or cracks have formed in dough, patch with reserved scraps. Return shell to oven and bake until bottom is golden brown, 15 to 20 minutes longer. Remove shell from oven and brush interior with egg white. Set aside while preparing filling. Reduce oven temperature to 350 degrees.

Garnish

• 2 tablespoons butter
• 2 large shallots, diced
• 12-14 ounces sliced mushrooms (we used one 3.5 ounce package of oyster and one of shiitakes and made up the difference with cremini)
• 5 tablespoons fresh thyme, minced
• 7 ounces Gruyère, shredded (roughly 1 and 1/2 cups)

Filling

• 1 1/2 tablespoons cornstarch
• 1 1/2 cups whole milk
• 8 large eggs plus 1 large yolk
• 1 1/2 cups heavy cream
• 1/2 teaspoon table salt
• 1/4 teaspoon ground black pepper
• 1/8 teaspoon grated nutmeg

1. Melt butter in large nonstick skillet over medium heat. Add shallots; sauté until soft, about 2 minutes. Add mushrooms; sprinkle with salt and pepper. Increase heat to high and sauté until liquid is absorbed and mushrooms are tender, about 8 minutes. Sprinkle with 2 1/2 teaspoons thyme and cook 1 minute. Transfer mixture to plate. Cool mushrooms completely.
2. Place cornstarch in large bowl; add 3 tablespoons milk and whisk to dissolve cornstarch. Whisk in remaining milk, eggs, yolk, cream, salt, pepper, and nutmeg until mixture is smooth.
3. Sprinkle blind baked crust with remaining 2 1/2 teaspoons thyme. Scatter mushrooms and Gruyère evenly over thyme. Gently pour custard mixture over filling. Using fork, push filling ingredients down into custard and drag gently through custard to dislodge air bubbles. Gently tap pan on countertop to dislodge any remaining air bubbles.
4. Bake until top of quiche is lightly browned, toothpick inserted into center comes out clean, and center registers 170 degrees on instant-read thermometer, 1¼ to 1½ hours. Transfer to wire rack and let stand until cool to touch, about 2 hours.
5. When ready to serve, use sharp paring knife to remove any crust that extends beyond edge of ring. Remove ring, then slide quiche onto serving plate. Cut into wedges and serve.

Our quiche was actually done before 1 and 1/4 hours... cresting well over 170 when we first checked... but luckily it didn't curdle. I guess maybe the cornstarch did the trick? But you might want to check on it a little early. While it took a long time to prepare, a lot of that time is just waiting around, and other than rolling the pie crust (a task I still farm out to Anna) nothing about it is particularly hard. You can use pretty much anything as a garnish according to Ruhlman, but make sure you don't use so much that it overwhelms the custard... since more of that texture is the whole reason for doing the "deep dish" version in the first place. Since I was picking my garnish from recipes based on a pie plate, I was reasonably certain it wouldn't have any problem with too much... but I honestly don't think there is anything I would do differently with this recipe (except keeping a closer eye on it in the oven).

Totally worth making in my opinion.