Vegetarian Black Bean Soup

This soup was not the most exciting bean soup I've had, but it was a fine meal and we ended up eating it all, so I guess I'd call it a success.

For this you will need,
4 c. cooked black beans (or 2 cans)
1 onion, chopped
2 tbsp. butter
2 stalks celery, chopped
1 1/2 tsp dried mustard
2 tbsp lemon juice
salt & pepper to taste

Directions:
In a cast iron skillet, melt butter.
Add onion and celery and cook until onion is translucent, stirring often.
Put black beans and onion and celery through a food processor.
Return to skillet and heat, stirring occasionally, until simmering.
Add mustard, lemon juice, salt & a lot of black pepper.

Serve in soup bowls with sour cream, cilantro, cheese, or whatever topping you like.

You could also add a ham bone and/or chopped ham to this.