Vegetable stock, whether store-bought or homemade, is one of those essential cooking ingredients that serves so many purposes. Whether you call it broth or stock (though there is a difference), it's perfect as the base for soups or in place of plain water for pasta or braised meats. But the core ingredients — potatoes, onions, celery, carrots — often produce rather mild results on their own. To add a little more oomph to your stock, amp up the umami flavor profile.