In a large soup pot, saute the onions, carrots, mushrooms and celery in the butter over medium-high heat for about 7 to 8 minutes.
Add the beef stock, Worcestershire sauce, and sweet potatoes. Bring to a boil and then lower heat to simmer.
Add the cooked beef to the pot, crushed red pepper and season with a little salt & pepper. Simmer for about an hour with the cover on.
Remove the cover, add the black and red beans and simmer for an additional ½ hour to 1 hour with the cover off.
Taste and adjust seasoning with salt & pepper.