Sausage breakfast casserole is a convenient and delicious way to feed a crowd for brunch. Combing savory sausage, fluffy eggs, and gooey cheese creates a comforting and satisfying dish that everyone enjoys.
Heat the Oven – Set the oven rack to the center position. Preheat to 350ºF (177ºC). Grease a 9×13-inch baking dish with olive oil on the bottom and sides.
Saute the Sausage – Heat a large pan or cast iron skillet over medium heat. Once hot, add in the sausage. Use a spoon to break it into smaller chunks. Saute until fully cooked and browned, about 3 to 4 minutes. Evenly spread into the baking dish. Drain off most of the fat from the pan.
Saute the Potatoes – Heat the pan over medium-high heat. Add 2 tablespoons of olive oil. Once hot, add the potatoes. Saute until tender, occasionally stirring, about 8 to 10 minutes.
Saute the Mix-ins – Turn the heat down to medium. Add the onions and garlic and saute for 1 minute. Add the bell peppers and saute for 2 minutes. Turn off the heat and stir in ½ teaspoon salt, black pepper, and green onions.Transfer the mixture to the greased baking dish, mix it with the sausage, and spread it into an even layer. Evenly sprinkle half of the cheddar cheese on top.
Add the Egg Base – In a large bowl, whisk together the cornstarch and 1 teaspoon salt. Add the half-and-half and eggs and whisk until thoroughly combined. Pour the egg mixture into the baking dish. Evenly sprinkle the remaining cheese on top.
Bake the Casserole – Bake for 20 minutes. Rotate the pan and continue baking until the center sets and a toothpick inserted comes out clean, about 20 minutes. The internal temperature should be 180 to 190ºF (82 to 88ºC). Cool for 10 minutes before slicing and serving.
Notes
Make Ahead: Assemble the casserole up to 1 day in advance, cover, and refrigerate. Baking time will be longer since the pan and ingredients will be cold.
Reheating Baked Casserole: Warm the whole casserole in a 300°F (149°C) oven until heated through. Cover with foil if it browns too quickly.
Freezing: Bake first, let cool completely, then wrap tightly in plastic wrap and foil. Freeze for up to 3 months. Thaw it overnight in the fridge and reheat it in a 300°F (149°C) oven until warm.
Storing: For leftovers, store in an airtight container for up to 5 days and microwave individual slices for about 1 minute.