We use mirepoix—a combination of onion, celery and carrots—to flavor this white bean soup. Keep a store-bought bag of the mixture in your freezer to ensure you always have some on hand without worrying about it going bad.
Put a large saucepan of water on to boil.
Heat oil in a large pot over medium-high heat. Add mirepoix and cook, stirring, until softened, about 3 minutes. Add garlic, Italian seasoning, salt, crushed red pepper and ground pepper and cook, stirring, until fragrant, about 1 minute. Add tomatoes and their juices, broth and beans and bring to a boil. Reduce heat to maintain a lively simmer. Cover and cook, stirring occasionally, until the tomatoes begin to break down, about 10 minutes.
Meanwhile, cook pasta in the boiling water for 1 minute less than the package directions. Drain.
Stir spinach into the soup. Stir in the pasta just before serving. Serve topped with Parmesan.