1 tablespoon unsalted butter 1 tablespoon olive oil 5 cups chopped leeks, white and light green parts (4 to 8 leeks) 4 cups chopped unpeeled white boiling potatoes (8 small) 3 cups chopped zucchini (2 zucchini) 1 1/2 quarts chicken stock or canned broth (48 oz) 1 teaspoon salt 1/2 teaspoon pepper 2 tablespoons heavy cream Fresh chives or julienned zucchini, for garnish

Heat the butter and oil in a large stockpot, add the leeks, and saute over medium-low heat for 5 minutes. Add the potatoes, zucchini, chicken stock, salt, and pepper; bring to a boil; then lower the heat and simmer for 30 minutes. Cool for a few minutes and then process through a food mill fitted with the medium disc. Add the cream and season to taste. Serve either cold or hot, garnished with chopped chives and/or zucchini.