Cut the steaks into 3cm pieces and place on a plate. Season well with salt and pepper.
Heat the oil in a large frying pan over a high heat and cook the steak until browned, about 2 mins each side. Remove with a slotted spoon and set aside.
Add the mushrooms, onions and thyme to the pan and cook for 10 mins, stirring frequently. Turn the heat up and add the tomato paste and some salt and pepper, cook for several minutes before adding the wine, then simmer until reduced by half.
Add the stock and bring to the boil, return the cooked steak and its juices and simmer gently until the meat is cooked to your liking.
