We answered this in the blog post 🙂 “Yes! You can make Egg Hash Brown Breakfast Casserole ahead of time. It’s best when eaten hot out of the oven, but it can be baked and then cooled/reheated. We don’t recommend mixing this together and leaving it in the refrigerator raw. The potatoes will soak up the eggs”

The recipe/substitutions says to omit the cheese if you are Whole30

There’s a storage section in the blog post that covers this – Yes, you can freeze Shredded Hashbrown & Egg Casserole, but we don’t recommend it. We find that frozen/reheated eggs can be a bit soggy but it will work!

I haven’t used all whites, but it turns out well substituting some of the eggs for egg whites. Let me know if you end up substituting all of them!

You can leave out the sausage!

I would like to leave out the sausage.