Dice the meat into bite-sized portions and flour it. Season with salt and pepper and mix everything well. In a small, ovenproof, earthenware pot put the onions (whole), carrots, celery, mushrooms and garlic and combine them well. Put the meat portions on top and stick the bay leaf and thyme sprig in. Add the prunes and pour the wine and meat stock over. Stir well. Put the lid on and bake at 200ºC for 1h and 45 minutes. Remove the lid and bake for another 15 minutes. Serve with potato mash and sprinkle with the finely chopped parsley. If you wish you may reduce the sauce before you serve. Put it in a saucepan and boil briskly over a high heat for 6-7 minutes until bubbling and thick. (you do that whenever you need to end up with a thick sauce).