Top bacon and leek quiche

6 rashers bacon 2 large leeks (white and light green parts), sliced, salt Freshly ground black pepper 2 tsp. fresh thyme leaves 6 large eggs 2 c. heavy cream 1 c. whole milk 1 tbsp. Dijon mustard 1/8 tsp. freshly grated nutmeg 6 oz. Gruyère, grated (about 1 1/2 cups) 1/2 c. chopped fresh flat-leaf parsley Mix basic pie dough. Chill and then roll into a 16-inch circle. Place in a deep 9-inch springform pan, lifting and pressing it into the bottom and up the sides of the pan; chill 1 hour. Poke bottom and sides of dough with a fork. Line with foil, leaving a 4-inch overhang. Fill with baking beans. Marbles or pie weights; chill 20 minutes. Heat oven to 425°F. Bake crust 15 minutes. Remove foil and pie weights. Cover edges with foil, and continue baking until completely dry, 8 to 12 minutes. Reduce oven to 325°F. Fry bacon in a large skillet over medium heat until crisp, 7 to 8 minutes; transfer to a paper towel-lined plate. Add leeks and season with salt and pepper. Cook, stirring occasionally, until soft, 6 to 7 minutes. Add thyme and cook 1 minute. Remove from heat; cool. Whisk together eggs, cream, milk, mustard, nutmeg, and 1/4 teaspoon each salt and pepper in a bowl. Fold in the Gruyère, parsley, and cooked leeks. Scatter bacon on bottom of crust, then top with egg mixture. Wrap pan with foil and place on a large rimmed baking sheet. Bake just until set around the edge but still wobbly in the centre, and a knife inserted it the comes out with no runny egg attached, 1 hour and 15 minutes to 1 hour and 30 minutes. Cool in the pan at least 30 minutes before unmoulding.