Cover the beans with water and soak overnight. In the morning, drain, and put in a large pot with the water, salt and ham bone. Cook for about 2 hours until the beans are soft. Remove the ham bone and skim the soup. Puree the mixture. Melt the butter in a saucepan, gradually add the flour, onion, pepper, mustard and the cream. Stir until slightly thick, then add to the bean puree. Simmer together for a few minutes and serve garnished with thin slices of lemon and hardboiled egg, or covered with Boola-Hoola Topping and run under the broiler until golden.
This topping will transform a number of soups into a very special affair. It is good on split pea soup, or split pea soup mixed half and half with canned green turtle soup, Boston black bean soup, lentil or tomato soup. This amount of topping will garnish six bowls of soup.
Combine egg yolk and cheese and mix to a smooth paste. Fold in the whipped cream. Swirl on top of soup in ovenproof bowls and brown quickly under the broiler. A tablespoon of Madeira or sherry added to the soup will make it even more festive.