Clean, wash and slice the mushrooms. Peel and chop the onion. Wash and quarter the tomato, remove seeds if necessary and dice finely. Wash thyme and pluck except for something to garnish
Toast roasting. Dab the fillet dry. Fry in hot oil in a coated pan for 1-2 minutes on each side. Season and remove. Fry the mushrooms and onion in the frying fat for about 5 minutes, season
Place the fillet, mushrooms and tomato on the toast. Sprinkle with thyme and cheese. Bake under the hot grill for about 5 minutes. Serve on salad. Garnish with rest of thyme