Put the browned Italian sausage, onion, mushrooms, green pepper, red pepper, Italian seasoning, oregano, curry powder, butternut squash soup, salsa, and water in a large freezer bag. Seal and squish to combine.
Remove excess air and seal. Freeze.
Thaw.
Pour the contents of the bag into a large skillet and cook over medium heat.
Top with grated Parmesan and red chili flakes if desired.