• On a lightly floured surface, roll the pie dough into a 16-inch round.
• Press the crust into a 10” tart or pie pan, firmly pressing it into the bottom and ridges. Trim excess dough, leaving a ¼” of overhang. Roll the overhang underneath the rim of the pie plate and crimp. Refrigerate for 30 minutes. 
  

Blind Bake:

• Preheat the oven to 375 degrees (F). Remove the crust from the fridge.
• Line the crust with parchment paper and fill with pie weights or dry beans.
• Bake in the lower third of the oven for 22 minutes. Remove from the oven. 
• Carefully remove the pie weights and parchment paper and prick the bottom of the crust all over with a fork. Place back in the oven and bake for 16 more minutes. Reduce the oven temperature to 325 degrees (F).
  

Quiche Filling:

• In a large skillet over medium-high heat, cook the bacon until crispy and brown, turning it frequently. Transfer to paper towels and drain. Chop into ¼-inch pieces and set aside. 
• Return the skillet to the stovetop. Reduce the heat to medium. Add the butter, then add the chopped onion and cook, stirring occasionally, until soft and slightly caramelized, about 15 minutes. 
• Transfer the onions to a small bowl and set aside until needed.
• In a large mixing bowl, add the heavy cream, milk, eggs, cornstarch, salt and pepper, cayenne pepper, nutmeg, and chives. Whisk vigorously for about 2 minutes.

Assembly and Baking:

• Spread the onions evenly over the bottom of the partially baked crust. Top with half of the bacon, all of the Gruyère, and then the remaining bacon, saving just a handful of bacon to sprinkle on top of the egg mixture. 
• Pour the egg/cream mixture over top, and sprinkle the reserved handful of bacon on top of the eggs. Place quiche on a large rimmed baking sheet.
• Bake, in the lower third of the oven, until the center is set and the crust is golden brown, about 55 to 65 minutes. If the crust/filling is getting too brown, cover it with a piece of foil but continue cooking.