Potato Leek Soup

5 leeks
5 Tbsp butter, split
3 cups potatoes
1 qt chicken broth
2 tsp salt
1/8 tsp cayenne
1/4 tsp nutmeg
2 Tbsp cornstarch, optional
1/2 c heavy cream

Wash the leeks. Split the leeks lengthwise and slice them finely,
including the white and light green parts. Wash the leeks again. Dice
the potatoes and cover them with cold water. Wash the leeks once more.
Melt the butter in a stockpot. Add the leeks and saute lightly, about 4
minutes. Drain the potatoes. Add the potatoes and broth to the leeks
and bring to a boil. Add the cayenne, nutmeg, and salt to taste. Simmer
over low heat for about 45 minutes. If desired, remove some or all of
the solids from the soup and put through a ricer or food mill. Return
to the broth. If desired, thicken with up to 2 Tbsp of cornstarch mixed
with a small amount of water. Add cream and remaining butter to soup
and serve hot with a dash of nutmeg and/or cayenne.