In a large pot over medium heat, drizzle a splash of olive oil. Add finely chopped onion, diced carrots, and chopped celery. Sauté for about 5 minutes until they're tender and the onion is translucent.

Stir in minced garlic and cook for an additional 30 seconds. Then, add sliced zucchini and trimmed green beans, stirring for about 3 minutes.

Add your choice of fresh or canned tomatoes to the pot. Pour in 6 cups of vegetable broth and bring to a gentle boil, then reduce the heat and let simmer uncovered for 10 minutes.

Stir in 1-2 teaspoons of Italian seasoning, plus salt and pepper to taste. Gently fold in the cannellini and kidney beans and let simmer for another 5 minutes.

Add a handful of fresh spinach and stir until it wilts, about 2 minutes. Taste and adjust seasoning before serving.