*Preheat the oven to 350°F.
Allow the crust to sit at room temperature for a few minutes, so it’s pliable. Unroll the dough and press it into your tart pan, easing it to (and up) the edges without stretching it. Trim off any excess dough that goes over the edges of the tart pan.
Lightly prick the bottom with a fork. Line the top with parchment paper and fill it with pie weights. Blind bake for 12 minutes. Remove the parchment and weights, then bake for 5-8 minutes more, until lightly golden. Set aside to cool.
Cook the shallots. In a small skillet over medium heat, sauté the shallots in 1-2 teaspoons of bacon fat for about 2 minutes, until softened.
Layer the filling in the tart crust. Sprinkle the bacon and shallots over the bottom of the pre-baked crust. Add half of the shredded Gruyere cheese.
Prepare the custard. In a large bowl, whisk together the eggs, heavy cream, salt, paprika, and nutmeg until smooth and fully combined. Pour the mixture into the crust, stopping about ¼ inch below the rim to prevent overflow. Sprinkle the remaining Gruyere over the top.
Bake the quiche for 30-35 minutes, checking at 30 minutes. The quiche is done when the edges are set and the center has a slight jiggle but is no longer liquid. It will continue to firm up as it rests.
Let the quiche rest for about 15 minutes before slicing. Garnish with fresh chives or parsley, if desired. Serve warm.