3 potato sausage and spinach breakfast casserole Recipes

eggs, heavy cream, kosher salt plus more, freshly ground black pepper plus more, unsalted butter, divided, fresh breakfast sausage links, sliced leeks, white and pale-green parts only, russet potatoes (1 1/2 lb), peeled, shredded, lightly squeezed, frozen spinach, thawed, squeezed dry, roughly chopped, grated gruyere, grated parmesan

vegetarian sausage links (such as morningstar farms), water , or more as needed, shredded sweet potatoes, butter, melted, shredded, reduced-fat mild cheddar-mozzarella cheese blend, chopped onion, sliced fresh spinach leaves, low-fat small curd cottage cheese, jumbo eggs