Steak royale

1) Flatten your steaks a little with a meat mallet ot a rolling pin.
2) Put 2 tbsp oil into a hot frying pan and fry turning regularly, according to taste.
3) Meanwhile heat remaining oil in another frying pan and sauté onion for 3 minutes.
4) Add mushrooms and cook for a further 2 minutes.
5) Add wine and simmer for 5 minutes.
6) Stir in cream, mustard, tarragon, garlic and seasoning and heat gently to warm, do not boil.
7) Serve steaks with sauce poured over.