01 - Heat oil in a large, deep skillet with a lid. Add crumbled sausage and cook, breaking it up, to 160°F for pork or beef or 165°F for poultry. Drain excess grease safely.
02 - Stir in garlic and Italian seasoning briefly. Add uncooked rigatoni, broth, cream and tomato sauce; stir so the pasta is distributed through the liquid.
03 - Bring to a gentle simmer and cover. Cook, stirring the bottom regularly, and begin checking the pasta after about ten minutes.
04 - If the pasta is still firm and the liquid is nearly gone, add hot water a small splash at a time. Continue until tender; the package shape and pan width may require longer than fifteen minutes.
05 - Fold in spinach and simmer until wilted. If sauce is too loose, cook uncovered briefly while stirring. Taste for salt, pepper and optional flakes, then serve.