Start by preparing your savory keto pie crust and pressing it into a 9-inch glass or ceramic pie plate. Pop it in the fridge to chill while you get the filling ready. This helps it bake perfectly!
Preheat your oven to 350°F (175°C).
Chop the bacon into small pieces. Cook it in a frying pan over medium heat until it's wonderfully crisp and golden, about 6 minutes. Take the bacon out and let it drain on a paper towel-lined plate to remove excess grease, keeping it nice and healthy.
In a medium bowl, whisk together the eggs, heavy cream, water, salt, and pepper until it's light and frothy. A hand beater works great here!
Pour out most of the bacon fat from the pan, leaving just about a tablespoon. Add the finely chopped onions and thyme sprigs to the pan. Sauté them gently until the onions are soft and fragrant. Remove the thyme sprigs and take the onions off the heat.
Take your chilled pie crust from the fridge. Sprinkle about one-third of the shredded cheese evenly into the bottom. Follow with one-third of the cooked bacon and half of the sautéed onions. Repeat with another layer of cheese, bacon, and the remaining onions. Carefully pour the frothy egg custard mixture over the layers. Finish by scattering the last of the cheese and bacon on top for a beautiful finish.
Bake for 35 to 40 minutes, or until the edges are set and lightly golden, but the center still has a slight gentle jiggle when you carefully move it. This ensures a silky, not tough, custard. Let it cool in the pan for a bit before slicing and enjoying – this allows it to set perfectly.