Warm the aromatics. In a skillet over medium heat, add 1 tablespoon olive oil. Sauté onion, carrots, and celery with a pinch of salt for 5–7 minutes until slightly softened. Stir in garlic for 30 seconds. This step boosts flavor, but you can skip it if short on time.

Load the slow cooker. Add the sautéed vegetables to the slow cooker along with potatoes, zucchini, green beans, crushed tomatoes, tomato paste, broth, kidney beans, cannellini beans, bay leaf, oregano, thyme, red pepper flakes (if using), and the Parmesan rind (if using). Season with 1 teaspoon salt and 1/2 teaspoon black pepper to start.

Set and simmer. Cook on Low for 6–8 hours or on High for 3–4 hours, until the vegetables are tender and the flavors are rich.

Add the pasta. About 20–30 minutes before serving, stir in the dried pasta. Cook on High until the pasta is just al dente. If the soup looks thick, add more broth or hot water to loosen.

Finish with greens. Stir in spinach or kale for the last 5 minutes, just until wilted and tender.

Taste and adjust. Remove the bay leaf and Parmesan rind. Add more salt and pepper as needed. A small squeeze of lemon brightens the whole pot.

Serve. Ladle into bowls and top with chopped parsley or basil and a generous shower of grated Parmesan. A drizzle of olive oil is a nice touch.