leek recipe

3 large leeks, white and light green parts only, cleaned and sliced - 2 tablespoons butter - 1 medium onion, chopped - 3 cloves garlic, minced - 4 medium potatoes, peeled and diced - 4 cups chicken or vegetable broth - 1 cup heavy cream - Salt and black pepper to taste - Fresh chives or parsley for garnish (optional)