This is a great breakfast or brunch dish. The potatoes and eggs meld together and transform into a gratin-like dish after baking. The edges are crispy brown like hash browns, but the center is a traditional Quiche Lorraine with eggs, bacon, onion and cheese. It smells and tastes quite rich, but it actually has fewer calories than a traditional Quiche Lorraine. So feel free to indulge without any lingering guilt! And like other quiches, it keeps well in the fridge and freezer.
Preheat oven to 425°F (220°C) with the oven shelf in the top 1/3 of the oven. Grease a 9-inch (23cm) pie dish (don't use a pie dish with a removable bottom or you run the risk of the filling leaking through).
Take a handful of the thawed hash browns and, squeeze the excess water out, then place into a large bowl. Repeat with remaining hash browns. You should have about 4 cups of shredded hash browns. Add melted butter and salt, and mix to combine.
Place the hash browns in the pie dish. Spread the hash browns over the base and side of the pie dish, and pat down the base of the hash brown crust so it is fairly firmly packed. Spray the hash brown crust with oil spray.
Bake the crust for 30 minutes.
While the crust is baking, melt 1/2 tablespoon butter in a skillet over medium high heat. Add onion, garlic and bacon, and sauté until the onion is translucent and the bacon is just starting to brown (but not crisp). Remove from the stove and set aside to cool slightly.
Place Egg Mixture ingredients in a bowl, and whisk to combine.
When the crust is light golden brown on the surface of the base and golden brown on the walls of the crust (around 30 minutes), remove from the oven. Scatter the bacon onion mixture across the base, then top with the cheese. Then pour the egg mixture on top.
Return the quiche to the oven and turn the oven down to 350°F (180C). Bake for 25 minutes, or until the filling is set. Test this either by inserting a skewer into the center (it should come out clean) or by gently touching the center (it should spring back). Let it rest for 5 to 10 minutes before serving.