In a large pot, cook sausage, ground beef, onion, and garlic over medium heat until the meat is browned and the onion is translucent.
Add all the tomatoes, water, sugar, basil, fennel seeds, Italian seasoning, cayenne pepper, crushed red pepper, chili powder, 2 tsp salt, and black pepper. Simmer, covered, for 1.5 hours. Stir occasionally.
Steam the spinach for about 2 minutes. Set aside.
In some oil, cook the mushrooms in a pot until tender. Drain the liquid, and set aside.
With 10 minutes left in the cooking time, stir the spinach and mushrooms into the sauce.