Thaw frozen potatoes and squeeze as much moisture out of them as possible. (This is easiest if you lay them across a layer of paper towels to thaw!)
Sautee Bacon, Onion and Garlic together in butter until bacon is starting to brown (but not crispy) and onions are clear. Set aside.
Hash Brown Crust
Preheat oven to 425 degrees
Grease a 9" quiche dish with butter
Add potatoes, butter and salt to a bowl and mix well.
Pour potato mixture into the quiche dish and press across the bottom and sides with your hands or a spatula.
Spray the mixture with oil spray. Bake for 30 minutes.
Add eggs, milk, cream, salt, and cinnamon to a bowl. Whisk until well mixed.
When the crust is baked, switch the oven to 350 degrees.
Cover the crust layer with bacon, onion and garlic mixture. Next, sprinkle a layer of cheese. Throw in a handful of spinach. Pour egg mixture over all of that and bake for 25 minutes or until cooked through.