Gently press your savory keto pie crust into a 9-inch glass or ceramic pie plate. Pop it in the refrigerator to chill while you get the filling ready.
Set your oven to 350°F (175°C).
Chop your bacon into small pieces and cook them in a frying pan over medium heat until they're beautifully browned and crisp (about 6 minutes). Take the bacon out and let it drain on a paper towel-lined plate to remove excess fat.
In a medium bowl, combine the eggs, heavy cream, water, salt, and pepper. Beat this mixture with a hand beater until it's light and frothy.
Pour out most of the bacon fat from the pan, leaving just about a tablespoon. Add the chopped onions and fresh thyme sprigs to the pan and sauté until the onions are soft and fragrant. Remove the thyme sprigs and take the onions off the heat.
Retrieve your chilled crust. Layer one-third of the shredded cheese at the bottom, followed by one-third of the cooked bacon and half of the sautéed onions. Add a second layer of cheese, the remaining onions, and another third of the bacon.
Carefully pour the frothy egg custard mixture into the crust. Top with the final layer of cheese and the last of the bacon.
Bake the quiche for 35 to 40 minutes. It's done when the edges are set but the center still has a slight jiggle.
Let the quiche cool in the pan to room temperature before slicing and enjoying. This helps it set perfectly!