Cook the macaroni in boiling salted water for 7 minutes, drain and return to the pan. Mix in the soup with half a can of water, borlotti beans, peas and 50g Walnuts, bring to the boil and season.
Transfer to a 2 litre serving dish. Mix together the breadcrumbs, Cheddar and remaining Walnuts and sprinkle over the pasta. Bake for 20 minutes until golden.
