Peel and small dice the onion. Peel and mince the garlic
Heat a large pot over medium heat. Once hot add oil and swirl to coat the bottom
Add onion and garlic to the pot to cook, stirring frequency until softened, 4-5 minutes
Use the tip of a knife to cut the sausage casing. Add the sausage to the pot and discard the casings. Use a spoon to break apart the meat. Cook, stirring occasionally, until pork is brown and crumbly, 6-8 minutes
Coarsely grate the mozzarella and finely grate the parmesan
Add gnocchi, diced tomatoes with their juices, water, Italian seasoning, and salt to the pot. Cover and cook on medium heat until chocchi is cooked through, 3-5 minutes. Remove from heat
1/2 cup water
Wash and dry the spinach. Add spinach to the pot a handful at a time while stirring to let it wilt before adding the next
Sprinkle with both cheese and let sit for 3-5 minutes or until cheese is melted