Spray your slow cooker with nonstick spray and place half of the hashbrowns in an even layer on the bottom.
Spread half of the bacon, sausage, canadian bacon, bell pepper, onion, and shredded cheese over the top of the hashbrowns. Start with the meat and end with the cheese.
Repeat the layers, starting with the hashbrowns, meats, and veggies, but save the other half of the cheese for later.
In a medium mixing bowl, thoroughly mix the eggs, salt, pepper, milk, and the garlic if you’re using it.
Pour the egg mixture all over the top of the casserole. It will not fill up the casserole, but trust me, it will hold everything together.
Top the casserole with the remaining cheese.
Cover and cook on high for 3 hours or or on low for 6-7 hours.