In a large, heavy pan, lightly brown onion in butter and bacon drippings.
Add brisket and liver and brown on all sides.
Sprinkle with paprika and flour, and blend in consomme.
Cover and simmer very slowly for 1 hour, stirring occasionally.
Remove liver and mince, then return to pan along with green pepper.
Simmer 1 hour longer, or until meat is tender.
Add potatoes and tomatoes, heat through.