Make the dough. Cut butter into 1/2-inch cubes, place in a small bowl and chill in freezer or fridge. Place flour and salt in food processor and pulse a few times to combine. Scatter butter over flour mixture and pulse several times, until it resembles a coarse, crumblike meal.
Working quickly, add 4 tablespoons of iced water and pulse several times. Add 1 or 2 more tablespoons of water and pulse again, with slightly longer pulses. If necessary, add more iced water, a tablespoon at a time, and pulse until mixture forms large dough balls. The change will be quick and dramatic—you'll know when it's happened.
Form dough into a flattened patty—again, work quickly and handle the dough as little as possible—and wrap with plastic wrap and refrigerate at least 1 hour and up to 3 days.
Par-bake the crust. Preheat the oven to 375ºF. Grease a 9- or 10-inch glass pie plate, or a tart pan with a removable bottom, with butter. Roll the dough out on a lightly floured surface to about a 1/8-inch thickness (more important, it should obviously be larger than your pie plate). Gently transfer it to the pie pan; Marion showed me a trick of folding it back over the rolling pin to lift it. You may also need a spatula to unstick it from the table or other surface. Gently press it into the bottom and inner edges of the pan.
Pinch the edges of the crust into pleats extending a bit above the edge of the pie plate, because of inevitable shrinkage during baking.
Prick the bottom of the crust at 1/2-inch intervals with a fork. Lightly press a sheet of aluminum foil inside the crust and fill it with pie weights or uncooked rice or dried beans. Bake for about 15 to 20 minutes, until edges are slightly colored.
Meanwhile, prepare the filling. While the crust patty is chilling/the crust par-baking, fry bacon in a large, lidded skillet over medium heat until crisp and drain on paper towel; crumble into small pieces. Pour off bacon fat and wipe the skillet with a paper towel, but don’t wash it. Add 1 to 2 tablespoons of olive oil and 2 teaspoons of butter, swirling to combine. Add shallots to pan. Sauté until soft, about 3 minutes, stirring occasionally. Add garlic and cook, stirring, about 45 seconds. Add spinach a handful at a time, stirring it in. Cover and cook, stirring occasionally, until spinach is completely wilted, about 5 minutes. Remove from heat and let it cool.
Lightly beat eggs in a medium bowl and add half & half, and salt and pepper. When crust is ready, place it on a cooling rack and remove foil with weights. Sprinkle some of the goat cheese in the bottom of the crust, then add the spinach mixture, spreading across the crust. Add the rest of the cheese, then carefully pour egg mixture over everything, gently working everything with a fork to allow eggs to settle in around filling.
Bake the quiche. Transfer pan to oven and bake until filling puffs up and browns slightly, and is set, about 25 to 35 minutes. A knife or tester should come out clean when inserted in the middle. Cool on a rack for at least 10 minutes. Cut into wedges and serve. Quiche may be served warm—my preference—or at room temperature.