Black beans, also known as "turtle beans," are an especially tasty variety, and make a lovely soup. As with most dried beans, they are inexpensive while offering a bounty of fiber, protein, folic acid, potassium and magnesium. Do not salt dried beans while they are cooking as the salt slows down the softening process. And a word about the sherry commonly added to this soup: forget "cooking" wines or sherries. They contain lots of added salt and very little in the way of flavor. Do your palate and your body a favor and use a drinkable sherry in this recipe.

Ingredients
1 pound black beans
1 bay leaf
1 large onion, sliced
Salt to taste
A few cloves of chopped garlic
1 teaspoon dry mustard powder
1 cup dry sherry (not cooking sherry)

Instructions

1. Pick over beans to remove any dirt, stones or foreign objects. Wash well, then soak for 8 hours in ample cold water.
2. Drain beans and cover with a generous amount of fresh water. Bring to a boil over high heat in a large saucepan with the bay leaf. Skim off foam, lower heat, and simmer, partially covered, until beans are just tender, about 1 hour.
3. Add onion and continue to cook until onion becomes extremely soft, about 1 more hour.
4. Add salt to taste and garlic. Continue to cook, adding a little boiling water if necessary, until beans are very soft, about 1-2 hours more.
5. Remove bay leaf and turn off heat. Ladle beans in batches into a blender or food processor and puree, or use an immersion blender and puree soup directly in the saucepan.
6. Add dry mustard powder and dry sherry. Correct seasoning. Reheat and serve, adding any garnishes you wish, such as slices of lemon or freshly chopped herbs.

Food as Medicine: Black beans have levels of antioxidant compounds similar to the levels found in grapes and cranberries, which have long been regarded as rich sources.In beans, as with fruits and vegetables, deep, dark colors indicate high levels of antioxidant activity.