Cut and the leeks lengthwise and then slice into narrow strips. Wash the cut leeks by floating them in a large bowl of water, using your hands to stir them up and rinse the dirt off which sinks to the bottom.
Heat your sauce pan over medium high heat and add the butter to melt.
Add the leeks to the pan along with a tsp of salt and cook for 3-5 minutes, stirring frequently.
Reduce the heat to medium and cook uncovered for about 30 minutes until the leeks are very soft.
Peel and cube two potatoes
When the leeks are softened, add the potatoes and another tsp of salt plus enough of the chicken stock to cover it all.
Bring to a boil and then reduce to a simmer for another 20-30 minutes or until the potatoes are soft.
When soft, use a potato masher to mash the potatoes and leeks, and then finish with a stick blender to turn the soup into a creamy texture, adding more broth to keep it from getting too thick.
Season with salt and pepper to taste, and two splashes of Worcestershire sauce.
