leek recipe

**Ingredients:** - 4 large leeks (white and light green parts only), cleaned and sliced - 2 tablespoons unsalted butter - 1 large onion, diced - 4 cups chicken or vegetable broth - 4 medium potatoes, peeled and diced - 1 bay leaf - 1 teaspoon dried thyme - Salt and pepper to taste - 1 cup heavy cream or milk (optional) - Fresh chives or parsley, chopped, for garnish