Par-bake the crust. Preheat the oven to 375ºF. While the oven is heating, put the pie crust in its tin on the counter and let it thaw slightly, so you can prick it all over with a fork. Line the pie shell with foil or parchment paper, then weight it with dried beans or pie weights (does anyone actually buy these?). Bake the crust until slightly golden on the edges, about 15 to 20 minutes. Transfer to a cooling rack and remove weights, simply picking the foil or parchment at the corners.
Meanwhile, make the filling. Thoroughly drain the artichoke hearts, then coarsely chop them. Heat a large, deep sauté pan over medium flame. Add enough oil to coat the bottom, about 2 tablespoons. Add artichoke hearts and spinach to pan (you may need to add the spinach in batches. Season very lightly with salt (the artichoke hearts and cheese will add plenty saltiness to the finished quiche). Toss everything to coat with oil and cook, stirring frequently, for 7 or so minutes, until spinach has cooked way down (hint: the filling needs to fit inside the pie crust). Using a slotted spoon, transfer the artichoke/spinach mixture to a paper towel-lined plate and let it cool slightly, then top with another paper towel and gently press down to squeeze moisture from it.
Beat eggs in a bowl, then add half & half and beat to combine.
Assemble and bake the quiche. Spread the Dijon mustard in the bottom of the crust (this is optional, but the mustard sharpens the cheese flavors without imparting its own taste). Put artichoke/spinach mixture into the crust and gently spread with a fork to evenly distribute it. Sprinkle cheese evenly over the filling. Pour the egg mixture over the top, using your fork to gently help it settle in around the filling.
Transfer to the middle rack of the oven and bake the quiche until it has puffed up and is set and beautifully browned, about 25 to 35 minutes. You can test with a sharp knife to make sure the middle is set.
Cool on a rack at least 10 minutes, then serve. You can also serve it room temperature, but I think warm is best. See Kitchen Notes about reheating leftovers.