Instructions: Soak beans overnight in water. Add ham bone and simmer until beans start to become tender, about 1 hour. Mix in mashed potatoes until smooth. Add onions, celery, garlic and parsley and simmer until beans are soft, about 1 hour.

Remove ham bone, then dice meat and return meat to soup. Thin with hot water, if necessary (soup should be thick). Season to taste with salt and pepper. Garnish with lemon slices.

This recipe yields 10 to 12 servings.

Comments: The soup was said to have been added to the cafeteria daily menu by mandate of Sen. Thomas Dubois of Idaho, who served as chairman of the committee in charge of the Senate cafeteria from 1901 to 1907. Another story credits Sen. Knute Nelson of Minnesota for requesting his favorite bean soup from Senate cafeteria chefs in 1903, when it first appeared on the menu.

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