In the bowl of a food processor fitted with a steel blade, add the flour, salt and sugar and pulse for 3 seconds.
Place the butter and Crisco on top of the flour mixture, spacing the butter and Crisco out. Pulse until the large pieces of butter are mixed into the flour, about 6 1-second pulses.
Add 4 Tablespoons of ice water and pulse 5-6 times, the dough should resemble coarse cornmeal. Transfer the dough to a medium mixing bowl.
Sprinkle 1 tablespoon of ice water over the dough. Use your hands to knead the dough until the dough comes together. Add the last tablespoon of water if needed.
Form the dough into a ball and then flatten into a 4-5 inch disk. Wrap in plastic and chill in the refrigerator for at least 30 minutes, or up to 1 day.
Remove the dough from the refrigerator and let it stand at room temperature for about 10-15 minutes to let the dough soften slightly so that it can be rolled out.
Roll the dough out on a lightly floured surface to a 12-inch circle that is about 1/6-inch thick. Gently fold the dough into quarters and carefully move the dough to a 9-inch pie pan. Unfold the dough and gently work the dough into the corners of the pan by carefully listing the dough with one hand and pressing with the other. Cut the dough so only 1/2 inch extends beyond the lip of the pie pan. Crimp the edges of the dough with your forefinger and thumb. Chill the pie shell in the freezer for 30 minutes.
While the pie shell chills, move the oven rack to the middle position and preheat to 375 degrees F. Press a 12-inch piece of heavy-duty foil inside dough shell. Fill the shell with 1 cup of pie weights or 2 1/2 cups of dried beans. Bake the pie shell until the dough dries out, about 17-18 minutes. Carefully remove the foil and pie weights (or beans) and continue to bake the pie shell until the crust turns light golden brown, about 7-10 more minutes. Keep the oven on and move the pie shell to a wire rack to cool while you make the quiche filling.
FOR THE QUICHE FILLING:
In a 10-inch skillet over medium heat, cook the bacon until brown and crispy, about 5-6 minutes. Transfer the bacon to a paper-towel-lined plate. Place the Parmesan and Gruyère cheese in the bottom of the pie crust, and bread into an even layer. Scatter the bacon over the cheese. Place the pie shell on a rimmed baking sheet and set aside.
In a medium bowl whisk together the eggs, egg yolks, half-and-half, salt, pepper, nutmeg, and cayenne pepper until combined. Pour the egg mixture into the pie shell to about 1/2-inch below the crust rim. Carefully transfer the rimmed baking sheet with the quiche on it to the oven. Bake for 35-40 minutes, or until the quiche is golden brown and a knife inserted about 1 inch from the edge comes out clean.
Transfer the quiche to a wire rack to cool. Serve the quiche warm or at room temperature. Garnish with freshly chopped parsley (optional).