Heat the olive oil in a pan and add the onion, cooking for 2-3 minutes, until softened.
Add the carrots, zucchini, tomatoes and tomato paste. Cook for 5 minutes, until softened, then add the dried rosemary, smoked paprika, cumin and turmeric. Continue cooking for 2-3 minutes more.
Add the tinned tomatoes, veggie broth, green lentils and potatoes. Simmer for 12-15 minutes, stirring frequently, over a medium heat, until the lentils are softened and the potatoes are fork-tender.
Stir in the butter beans and cook for a few minutes more, before serving.
