Make this casserole the night before and bake it in the morning. Sausage, eggs, cheese — a low carb breakfast that feeds the house without any bread or toast.
Preheat the oven to 350°F. Grease a 9x13-inch casserole dish with butter or oil.
In a large skillet over medium heat, cook breakfast sausage until browned and fully cooked. Drain excess fat and spread sausage evenly in the prepared casserole dish.
In a mixing bowl, whisk together eggs, heavy cream, salt, black pepper, and garlic powder until smooth and frothy.
Add the sliced green onions and half of the shredded cheddar cheese to the egg mixture and stir to combine.
Pour the egg and cheese mixture over the sausage in the casserole dish. Top with the remaining cheddar cheese.
Cover and refrigerate overnight or bake immediately for about 40–45 minutes, until the casserole is puffed and golden, and the center is just set.
Let the casserole rest for 5–10 minutes before slicing to allow the texture to settle. Serve warm.