Carrot Soup

Ingredients

• 1 1/2 lb. potatoes, peeled and chopped
• 1 1/2 lb. large carrots, chopped
• 3 large leeks, white parts only, finely sliced
• 3 tablespoons butter or olive oil
• 3 cups water
• 3 cups chicken broth
• 1 teaspoon thyme
• 1 tablespoon dill
• salt to taste
• half-and-half, cream, or plain yogurt (optional)
• 1/4 cup finely chopped fresh chives or parsley