Set a large soup pot over medium to medium-low heat. Add chopped bacon and cook gently until just crisp, stirring regularly. Do not let the bacon burn. Use a slotted spoon to remove bacon to a paper towel-lined plate and set aside.
Remove all but 1 tablespoon of bacon grease from the pot and set heat to medium. Add the sausage slices. Brown one side of the sausage, then use a slotted spoon to remove it to the plate with the bacon.
Add the butter to the bacon grease. Once butter has melted, stir in the onion, carrots, celery, and leek, and saute for about 4 minutes, stirring regularly, just until slightly softened. Stir in garlic and cook for 1 more minute.
Add the chicken broth, potatoes, bay leaves, marjorum, salt, and pepper. Increase heat a little bit and bring the soup just to a boil. Then immediately lower the heat to medium-low and simmer, partially covered, for 10-15 minutes, or just until veggies are almost tender.
Add the bacon and sausage to the soup, followed by the half & half, and simmer 5 minutes more or until everything is perfectly tender. Taste test and add more salt and/or pepper if needed.
Serve hot, with chopped fresh parsley sprinkled over individual bowls of soup.