Heat the oven to 350 degrees F. Line a baking sheet with parchment paper.
Lay out 6 horizontal strips of bacon on the prepared baking sheet. Fold every other strip of bacon in half onto itself and lay one strip of bacon in the middle, vertical to the folded strips. Unfold the strips back over the vertical strip of bacon. Repeat this process using alternating vertical strips to weave into a lattice. (The bacon lattice should have an equal number of horizontal and vertical strips.) Bake until nearly cooked but still very pliable, about 15 minutes. Slide the bacon lattice into a 9-inch pie pan and press into place.
Top the bacon with a paper towel, then a layer of foil and either another pie pan or pie weights to weigh it down. Allow to cool for 10 minutes, then remove the weights and pat off any remaining excess oil with a paper towel.
Meanwhile, thoroughly mix together the eggs, milk, spinach, potatoes, some salt and pepper and 1 cup of the Cheddar. Pour the egg mixture into the bacon crust and top with the remaining cup Cheddar.
Bake until set and the cheese is browned, 30 to 45 minutes. Let rest 5 to 10 minutes, then serve warm or room temperature.