Instructions 

1. In a large mixing bowl, combine the all-purpose flour, small cubes of cold butter, and kosher salt. Use your fingertips to squeeze the cubes of butter into the flour, flattening them out into small sheets of flour-coated butter. Continue squeezing the flour into the butter for 3-4 minutes until the mixture is crumbly.
2. Add the ice water and use a spatula or wooden spoon to combine. The dough will just start to come together but will still be very crumbly and shaggy. Line the work surface with a piece of plastic wrap, then pour the shaggy dough onto the plastic wrap. Use the plastic wrap to gather the dough together and press it into a disc shape. Chill in the refrigerator for at least 45 minutes.
3. Remove the dough from the fridge, cut the disc in half and stack the two halves on top of each other. This will help create even more flakey layers. Flour your work surface generously, then sprinkle extra flour on top of the dough. Roll the dough out into a 12-to-14-inch circle.
4. Spray a 9” pie plate/round baking dish with nonstick cooking spray. Lay the crust dough into the prepared dish. Trim the edges, and crimp if desired. Place the shaped crust back into the fridge for 15 minutes to firm up. Meanwhile, preheat the oven to 400°F. Remove the dough from the fridge, and place a piece of parchment paper in the center of the dough. Then pour pie weights or raw beans into the pie plate. This will keep the crust from sinking as it bakes, and it’s called “blind-baking.”
5. Bake for 30 minutes, then remove the parchment paper and pie weights, lower the oven temperature to 350° and bake for another 5 minutes. Set aside to cool.
6. Prepare the filling: In a large skillet, sauté the leeks in 1 tablespoon of olive oil until softened and slightly caramelized. Add the mushrooms, and cook for another 2 minutes until softened, and finally add the garlic, and cook for another 2 minutes. Spoon the vegetable mixture into a medium size mixing bowl.
7. In the same pan, add the spinach, and cook over medium heat until wilted but still bright green. Spoon the spinach into the bowl, discarding any water. Add the spinach to the mixing bowl.
8. Preheat the oven to 350°F. To another large mixing bowl, add the milk, heavy cream, eggs, kosher salt, pepper, and nutmeg. Whisk well to combine. Add the sautéed vegetables to the bowl and combine. Finally add the cheese and fold in.
9.  Place the baking dish on a baking sheet to make transferring it to the oven easier. Pour the quiche filling into the cooled crust and bake for 4-45 minutes until the filling is set. Enjoy! 

Recipe by Lion’s Bread.