Stand mixer with paddle attachment
One 9″-diameter deep pie dish
In a stand mixer with paddle attachment, combine sugar, and 2 cups of flour until combined. Add butter mix until it resembles a coarse meal with a few pieces of fat visible. With the mixer running, drizzle in 6–7 Tbsp. ice water and combine until dough is still crumbly but just holds together when squeezed.
Turn out dough onto a work surface. Knead 1–2 times, pressing to incorporate any shaggy pieces. Press into a 6″-wide disk. Wrap with plastic wrap and chill at least 1 hour. (The dough can be made 3 days ahead; keep chilled, or freeze up to 2 months.)
Place rack in lowest position of oven; preheat to 375°. Roll out dough on a lightly floured work surface to a 14″ round. Transfer the dough to the pie dish. Pick up edges and allow dough to slump down into dish, letting excess dough hang over dish. Trim so the excess is even and pinch and crimp around the edge to finish the border. Dock the bottom of the dough. Chill 30 minutes.
Line dough with foil, leaving some overhang. Fill with pie weights or dried beans. Bake until the crust is dry around the edges and just beginning to brown, 25–35 minutes. Carefully remove parchment and weights and reduce oven temperature to 350°. Bake until crust is set and beginning to brown in the center, 15–20 minutes. Let the crust cool before assembling the quiche.
Cook bacon, onion, butter, thyme, and bay leaf in a small saucepan over medium high heat, stirring occasionally, about 5 minutes. Reduce heat to low (mixture should still slowly bubble) and cook, stirring occasionally, until bacon and shallots are very soft, about 20 minutes. Let cool. Strain through a fine-mesh sieve; pluck out thyme and bay leaf. Reserve bacon and onion.
Place rack in middle of oven; preheat to 350°. Purée eggs in a blender on medium-high speed until foamy, about 30 seconds. Add half-and-half, salt, cayenne, and nutmeg. Beat on medium-low until custard is smooth, about 15 seconds.
Place prepared pie dish on a rimmed baking sheet. Sprinkle cheese evenly over bottom of crust. Top with bacon mixture. Pour half of the custard into crust. Transfer quiche to oven, then carefully pour remaining custard into crust. Bake quiche until edges are set but center slightly wobbles, about one hour. Let cool before slicing. Serve warm or at room temperature.