Heat the butter in a non-stick frying pan, gently fry the onion rings over a medium heat for approx. 3 mins. until crisp, remove and set aside. Heat the butter in the same frying pan, add the carrots and spätzle, stir fry for approx. 5 mins. Reduce the heat, pour in the cream, season and simmer for a further 2 mins. Stir in the cheese and parsley, top with the reserved onion rings.