Mushroom Buttermilk Quiche

Make the shellSift flour into a large bowl. Add in the butter pieces, a handful at a time while mixing on low speed with a hand mixer. When all of the butter has been added, increase the speed to medium and mix until the butter is completely incorporated. Lower speed and add in water keep mixing just until thoroughly incorporated. Knead the dough together into a ball and flatten the into an 8-inch disk, wrap in plastic and refrigerate until chilled, at least 1 hour or overnight.Set a 9-inch quiche pan and line with parchment paper. Brush the inside of the ring with oil.Dust the dough on both sides with flour. On a lightly floured work surface, roll out the dough to a 16-inch round, about 3/16 inch thick. Carefully roll the pastry around the rolling pin and transfer to the prepared pan, pressing it into the corners. Trim the overhanging pastry to 1 inch and press it firmly against the outside of the ring. Use the trimmings to fill any cracks. Refrigerate the shell for 20 minutes. Fill any cracks with the reserved pastry dough.Preheat the oven to 375 ?/176C;. Line the quiche shell with a 14-inch round of parchment paper; fill the shell with dried beans or rice. Bake for about 40 minutes, or until the edge of the dough is lightly browned. Remove the parchment and beans and continue baking the pastry shell for about 15 minutes longer, or until golden brown on the bottom. Transfer the baking sheet to a rack and let the pastry cool.make the fillingIn a very large pot, heat the oil. Add the mushrooms, season with salt and pepper and cook over high heat, stirring, until starting to soften about 5 minutes. Reduce the heat to moderate. Add the shallots and thyme and cook, stirring often, until the mushrooms are tender, about 10 minutes longer. Season with salt and pepper and let cool.Scatter the mushrooms evenly over the bottom of the quiche Shell.In a blender, mix the milk, buttermilk and eggs and season with 1½ tsp of salt, â…› teaspoon of pepper and a pinch of nutmeg at high speed until frothy, about 1 minute. Pour the custard into the pastry shell.Bake the quiche for about 1 hours, or until richly browned on top and the custard is barely set in the center. Let cool in the pan until very warm.