1. Pound the steaks until thin.
2. Finely chop the onion and slice the mushrooms
3. Heat a skillet and add the oil.
4. Fry the steaks on a high heat, turning once. Remove from pan.
5. Add the chopped onion and cook 2 minutes. Pour in the sherry and bring to the boil.
6. Stir in the flour and mix well. Let cook for a minute and remove from the heat.
7. Stir in the water and crumbled stock cube.
8. Return to heat and stirring all the time until the sauce thickens.
9. Return steaks to pan, add mushrooms and mix well.
10. Season with salt & pepper.
11. Cover pan and simmer very gently for 15 minutes.
12. Serve with noodles, rice or mashed potatoes.