In a medium bowl, mix together hash browns, Canadian bacon and onion. Season with garlic powder, salt and pepper to taste. Add 1/2 the cheese.
Spread potato mixture over the bottom of a sprayed 9x13 inch baking dish; set aside.
In another bowl, beat eggs, season with salt and pepper and whisk in milk.
Whisk in Bisquick (make your own - recipe here: https://riseandshinerecipes.com/homemade-bisquick/ )and beat until smooth. Add remaining cheese. Mix well Pour over the top of the hash brown mixture. Bake, uncovered, at 400 for about 30 minutes or until set. Let cool slightly before cutting. Cut into 6 or 8 servings.