Preheat the oven to 350ºF and grease a 9″x13″ baking pan. (Don’t heat the oven if you’re doing the make ahead option.)

Fry the sausage in a large pan over high heat until browned and cooked through. Then add the green onions and garlic and reduce the heat to medium. Cook 1-2 minutes, then add the spinach and bell pepper, and continue to cook just until the spinach wilts. Remove the pan from the heat and set it aside.

Add the frozen hash browns to the prepared baking pan. Top the hash browns with the spinach mixture, and spread it out as evenly as possible.

In a medium sized bowl or in a blender, add the eggs, salt, pepper, and milk of choice. Whisk or blend until smooth. Pour the egg mixture over the hash browns and spinach mixture. Stir to evenly distribute the ingredients.

If you’re making this ahead, tightly cover the casserole and refrigerate for up to 2 days before baking.  When you are ready to bake the casserole, remove it from the fridge to take the chill off while the oven preheats. Also be sure to check if your baking dish can go from the fridge to the oven, (I use Pyrex). It also takes about 5 additional minutes to bake coming from the fridge.

Otherwise if your baking this right away, place the casserole in the oven as soon as it’s assembled. Bake until puffy and the center is done, 35-40 minutes.

Remove the casserole from the oven and serve immediately. Or you can let it cool to room temperature, portion it out and refrigerate it for future breakfasts.

Any leftovers also freeze beautifully for a later date. Thaw the frozen casserole or pieces of the casserole in the refrigerator overnight and reheat as desired.