PAT THE MEAT DRY, SPRINKLE with salt and pepper. Heat the oil in a large flame-proof casserole, add the meat and brown on both sides over high heat. Remove the meat from the pot, reduce heat to medium and add onions, carrots and celery and cook, stirring, for five minutes. Stir in the flour, then add the wine and broth. Replace the meat in the casserole, add the thyme, cover and cook over low heat until meat is tender, about one hour. When the meat is tender, remove it from the pot and strain the sauce. Discard vegetables. Slice the meat and arrange on a platter. Serve the sauce separately.