Mix together the KNORR Cheese, Ham and Mushroom Pasta and Sauce sachet contents, milk, water and margarine.
Bring to the boil, simmer for 8-10 minutes, stirring occasionally until cooked.
Heat the oil in a pan and fry the leeks, mushrooms and sausage.
Add the pasta to the sausage mixture, mix well.
Place in an ovenproof dish.
Sprinkle the Parmesan cheese.
Bake in a preheated 180°C oven for 25 minutes or until golden brown.