Cut meat from bones, set aside, reserve bones and gristle. Add onions, celery, bay leaf, parsley, cloves, sugar, tomatos, bones, gristle and salt and pepper to water; heat to boil. Simmer covered for 1 hour. Meanwhile, cut meat in 1/4-inch dice and brown in butter. Strain broth and discard bones and vegetables. Add browned meat and drippings. Simmer for 20-30 minutes until meat is done and broth is richly flavored. Do not overcook. Serve hot.