Clean and slice leeks lengthwise.
Chop sliced leeks into 1/2 inch pieces
Wash and dice potatoes into cubes.
Put leeks, potatoes, onions, garlic, chicken broth, bay leaves, thyme, and cloves in a soup pot. Bring to a boil and then let simmer until all vegetables are tender, about 20-30 minutes.
Using an immersion blender, carefully (can "hot splash" back up at you) mix the soup until all large pieces of veggies have been blended and broth is smooth.
Add the whole milk and let simmer over medium heat until hot.
While the soup is heating again, use a ball blender to mix 1/2 cup of milk with the flour in a lidded container. When the soup has reheated, stir in the milk/flour mixture and keep stirring until thickened.
Add chopped parsley and/or chives, reduce heat, then serve. Top with bacon and shredded cheese of your choice (optional).