Heat a little oil in a frying pan. Add onion, garlic, carrot and celery and cook for 5 minutes. Remove to an oven-proof dish.
Season meat, brown in pan for 3-4 minutes each side and transfer to oven-proof dish. Add diced tomatoes, stock cubes (mixed with 3/4 cup boiling water), thyme, salt and pepper. Stir until well combined.
Cook covered in moderate oven (180c) for 1 1/2 to 2 hours until meat is very tender. Serve with steamed rice and garnish with extra thyme.