Heat the olive oil in a large saucepan over medium heat. Add the diced onion and cook for 5 minutes until soft.
Add the minced garlic and tomato puree, cooking for 1 minute.
Stir in the orzo, chopped tomatoes, butter beans, oregano, basil and vegetable stock. Bring to the boil.
Reduce to a simmer and cook for 12-15 minutes, stirring frequently, until the orzo is tender and the liquid has been absorbed into a creamy sauce.
Stir in the grated cheese and season with salt and pepper. Serve immediately while creamy.