1 In a large pot, heat oil and cook onion and garlic over low heat for about 10 minutes.
2 Meanwhile, rinse and chop the spinach. When onion is soft add spinach, stock, pepper, soy sauce, lemon zest and all of the beans, raise the heat to medium-high and cook until hot.
3 Puree with an immersion blender in the pot. Serve with croutons if desired.