Warm the pot: Heat olive oil in a large pot over medium heat. Add onion, carrots, and celery. Cook 4–5 minutes until the onion is translucent and the edges look glossy.

Add garlic and tomato paste: Stir in garlic and tomato paste. Cook 1 minute, stirring, until the paste darkens slightly and smells sweet.

Build the base: Add diced potato, zucchini, and green beans. Sprinkle in Italian seasoning, red pepper flakes if using, salt, and pepper. Stir to coat the vegetables with the seasonings.

Pour in liquids: Add the canned tomatoes (with juices) and vegetable broth. Drop in the bay leaf, and add a Parmesan rind if you have one. Bring to a boil.

Simmer quickly: Reduce heat to a lively simmer. Cook 12–15 minutes, uncovered, until the potatoes and green beans are tender but not mushy.

Add beans and greens: Stir in cannellini or chickpeas, then add spinach or kale. Simmer 2–3 more minutes until the greens wilt and the beans warm through.

Brighten and finish: Remove bay leaf and Parmesan rind. Stir in lemon juice or red wine vinegar. Taste and adjust with more salt, pepper, or acid as needed.

Serve: Ladle into bowls. Garnish with chopped parsley and a light sprinkle of grated Parmesan if you like. Add a drizzle of olive oil for a silky finish.