The meat is washed and placed in a clay casseroles. Add onion and Coca-Cola, salt and pepper to taste. Bake in hot oven 6-8 hours. In the last hour, add the chopped potatoes, carrots and mushrooms and cook for at least another hour. The meat must be removed very easily. If desired, you can cook in low oven, but it takes about 12 hours. To the remaining sauce and bits of meat add tomatoes, corn, celery, beans optional. Add sauce and mix and gets stew or soup.