Cook the sausage by heating a skillet over medium heat and adding your breakfast sausage. Cook for about 5-7 minutes, breaking apart until browned. Transfer to a plate to cool.

In a large mixing bowl, whisk together eggs, milk, and sour cream until smooth. Season generously with salt and pepper.

Grease a 9x13-inch baking dish. Layer half of the hash browns at the bottom, followed by half of the cooked sausage and a sprinkle of cheddar cheese.

Repeat the layering with remaining hash browns, sausage, and more cheddar cheese.

Pour the prepared egg mixture over the layered ingredients, pressing down gently.

Cover and refrigerate overnight.

Preheat the oven to 350°F (175°C). Remove covering and bake for 45 minutes, covered.

After 45 minutes, remove foil and bake an additional 20-25 minutes until golden brown and bubbly.

Let cool slightly, garnish with chopped green onions, slice, and serve.