Finely dice carrot, celery and onion and gently fry until soft with a few chopped sprigs of rosemary. Add a chopped garlic clove for last few mins.
Take the skin off of three Italian pork sausages (I use Sainsbury's) add the sausage meat to the veg, cook until browned.
Add tablespoon of tomato purée and a tin of chopped tomatoes, season and simmer for 20 mins or so.
Add cooked pasta ( I always use fusilli for this) and some chopped basil leaves and stir, serve topped with Parmesan. Simple and delicious.