This is a very short recipe
with very few ingredients:
makes 8 servings
2 cups sliced leeks (white part only)
3 tablespoons unsalted butter
1 lb peeled and cubed russets
1 lb peeled and cubed sweet potatoes
8 cups chicken broth
buttermilk, snipped chives for garnish
In a pot, sauté the leeks in the butter for 4 minutes.
Add the remaining ingredients (except the garnish) and salt and pepper to taste.
Simmer for 1 hour.
In a number of batches, puree in a blender.
Garnish with the buttermilk and chives.