Make-ahead Sausage Hash Brown Breakfast Casserole is loaded with bits of savoury sausage (meat or plant based), diced hash brown potatoes, onions, red peppers, eggs, herbs and lots of cheese. It’s a hearty all-in-one breakfast casserole.
Preheat oven to 375 degrees F. Generously grease a large and deep 10” x 15” casserole dish.
In a large skillet over medium high heat, add 1 tablespoon of the olive oil. Working in two batches, cook the de-cased sausage meat, breaking it up as it cooks until browned and caramelized. With a slotted spoon, transfer cooked sausage to an extra large 8 quart mixing bowl and repeat process with remaining sausage meat. Season cooked sausage with garlic powder, oregano and paprika.
Add remaining ½ tablespoon oil to the skillet and the onions. Sauté onions for 3 minutes, then add garlic and cook until fragrant for 1 minute. Add red pepper and sauté for 3 minutes. Transfer onions and peppers to the bowl with the sausages and toss to combine.
To the large bowl with the sausage mixture add frozen diced hash brown potatoes, 2 cups of the shredded cheese, green onions, 1 teaspoon of the salt and ½ teaspoon of the pepper. Toss to combine.
In another bowl whisk the eggs, milk, crushed red pepper flakes, remaining 1 teaspoon of salt and remaining ½ teaspoon of pepper. Pour egg mixture into the large bowl with the sausage mixture and toss well to combine.
Turn the mixed ingredients into the prepared baking dish, pack it down, and sprinkle top with the remaining 1 cup shredded cheese. Cover tightly with foil. Bake immediately or store in refrigerator overnight and bake the next morning. If refrigerated - follow directions in Recipe Note 7 below.
Bake for 40 minutes, remove foil and continue baking for an additional 5 - 10 minutes until golden and bubbly. Garnish with more sliced green onions.