Grease a large 6 quart slow cooker (or bigger) with cooking spray or butter.
Layer half the hash browns in the bottom of the slow cooker.
Top with half the sausage, bacon, cheese, onions, green pepper, and red pepper. Repeat layers with the remaining ingredients, except cheese.
In a separate large mixing bowl, whisk together eggs, milk, salt, pepper, and sour cream.
Pour over hashbrown and sausage layers.
Cook on low for 6-8 hours on low or 2-3 hours on high.
Sprinkle on remaining cheese and cover until melted.
Serve warm with lots of fresh toppings.
PLEASE NOTE: Not all slow cookers cook at exactly the same temperature. You may need to adjust the cook time to your specific device to avoid burning the edges, as some readers have reported.
This casserole is gluten free. Check the ingredients on your sausage and hash browns, to make sure.
Don't thaw the hash browns. It's not necessary and could cause them to dry out.
Add diced ham or other ingredients that you love in omelets, such as mushrooms or spinach.
Mix in a can of diced green chiles with the sausage for a Southwest style casserole.
To really make this breakfast shine, add lots of fresh toppings such as sour cream, tomatoes, salsa, avocado, green onion, or chives.
Consider getting a programmable Crock Pot with a timer, like this one. That way you don't have to worry about getting distracted or over-sleeping and overcooking!
How do you reheat leftovers? I just cut a slice and pop it in the microwave. If your microwave is big enough, you can transfer the remaining casserole to a baking dish and microwave the whole thing that way until heated through.
Can you freeze it? I don't recommend it. Eggs don't typically freeze well and have a rubbery texture when thawed.