Potato and Leek Soup

Cut bacon crosswise into thin slices. In a large saucepan over medium heat, cook bacon, stirring occasionally until crisp, 5 minutes. Add potatoes and leeks and cook until leeks are wilted, stirring occasionally, 5 minutes. Add water and bring to a boil over medium-high heat. Reduce heat to medium-low and simmer until potatoes are tender, 15 to 20 minutes. Stir in 1 cup milk, mustard, salt, and pepper. Working in batches, puree soup in food processor until smooth, about 20 seconds per batch. Return soup to saucepan and stir in remaining milk. In a small bowl whisk together the egg yolk and cream, then stir occasionally, 5 minutes. Add water and bring to a boil over medium-high heat. Reduce heat to medium-low and simmer until potatoes are tender, 15 to 20 minutes. Stir in 1 cup milk, mustard, salt, and pepper. Working in batches, puree soup in food processor until smooth, about 20 seconds per batch. Return soup to saucepan and stir in remaining milk. In a small bowl whisk together the egg yolk and cream, then stir into soup and simmer until hot. Garnish each serving with chopped parsley, and black pepper if desired. Makes 6 servings.