This is one of the most satisfying soups, made from two of the most humble ingredients! It is delicious served cold in the summer - and then it is called Vichysoisse.
Trim off the coarse green portion of the leeks and freeze to make soup stock later.
Cut leeks in half lengthwise, leaving the bulb end intact and clean well under running water. Shake off excess moisture and slice the leeks thinly, discarding the root end when you get to it.
In a stock pot, melt the butter over medium-high heat. Add the leeks and cook, stirring frequently about 4 to 5 minutes until soft.
Add the potatoes and stock (or water). Bring to a boil. Reduce heat to a simmer and cook about 30 minutes or until the potatoes are very soft.
Add the milk (or cream) and return to a bare simmer. Puree the soup with an immersion blender. If the soup is too thick, add more milk or cream.
Season with salt and white pepper to taste
Garnish with finely chopped chives, chopped crispy bacon, pancetta, or shredded duck confit.
6 servings