For pho to be considered authentic, it must include certain elements, like crispy browned onions on top of a broth spiced with star anise, cinnamon, fennel and clove. And it must contain noodles. But the principles behind what makes pho so compelling can be applied in many different ways, in various dishes, with and without noodles, or many other elements of traditional pho.
Stripped to its bare essence, the power of pho comes down to a savory broth to which fresh, aromatic herbs are added. The interplay of different flavors hitting different sensors, and contrasts between raw and cooked, meat and plant, and soft and crunchy, is what makes pho so exceptional.
Stripped to its bare essence, the power of pho comes down to a savory broth to which fresh, aromatic herbs are added. The interplay of different flavors hitting different sensors, and contrasts between raw and cooked, meat and plant, and soft and crunchy, is what makes pho so exceptional. Noodles, while a beloved tradition, don't need to be there for this magic to work. They are a chewy and fun means of consuming this extraordinary soup, but when I go out for pho, I often leave behind a wad of noodles in the bowl. I can guarantee my experience isn't diminished.
As for the authentic pho spices in the broth, they make for an amazing bowl of soup when done right. Add too much and it tastes oddly like pumpkin pie. And if you're veering off course from tradition, as I encourage you to do, I would err on the side of caution in terms of how you season the broth.
Pho, a hybrid of Chinese, Vietnamese and French cuisines, has always been a work in progress. Prior to the French occupation of Vietnam, beef wasn't commonly eaten there. The French brought not only their meat, but their technique for making the rich, savory bone stock that is fundamental to French cuisine. This bone stock was incorporated into a Chinese-influenced dish of noodles and meat that was already popular in the northern part of Vietnam.
"Pho" is often mispronounced as if it rhymes with "go," but the correct sound is more like "fuuh"—as if you were about to say a bad word and then realized you were in mixed company and switch mid-word to "fudge." Many American pho houses, aka Vietnamese restaurants, have latched onto the humorous possibilities of this sound, giving their restaurants names like "Pho King" and "What the Pho?"
Another theory is that "pho" comes from the Chinese "fun," a wide style of noodle from nearby Canton that is similar to the wide noodles used in northern, Hanoi-style pho. When Vietnam was partitioned in 1954, a flood of immigrants went south, bringing pho with them. It became established in Saigon, where thinner noodles were used in a sweeter broth. Most importantly, Saigon is where the side salad of raw herbs, sprouts, lime and chile peppers entered the pho-scape. This is when pho came of age and became the world-beater it is today.
From Saigon, pho morphed into the very similar "noodle soups" of Thailand and was adopted by other Southeast Asian cultures as well. It went on to win the hearts and bellies of Europe and the New World, inspiring giddiness, professions of love, proclamations of addiction and endlessly repeating customers in the restaurants where it is served. But the essence of the many permutations of pho comes down to dropping fresh herbs in a watery, savory soup.
While bone broth is impossible to replicate, some decent vegetarian versions of pho broth are made with roasted daikon radish and mushrooms. This takes a lot more skill than throwing some bones in water, be they beef, lamb, chicken or venison. In both vegetarian and meat broths, soy sauce should be used instead of—or in addition to—salt because it delivers more umami. Bone broth is the primary source of umami, which is an important part of the pho flavor equation, but a diversity of umami helps. Fish sauce, traditionally used in pho, adds umami as well. Oyster sauce works too.
The other day I made goat soup with potatoes, carrots, celery and zucchini. It was a fairly normal pot of meat soup, seasoned (mildly) with thyme, no less. Served with basil, lime, green onion and cilantro, the spirit of pho ran strong in that bowl.
I've also made faux-pho with stock from a chicken carcass in which lamb stew meat was simmered until tender, with veggies added for the last hour of simmering.
Durable ingredients like onion, potato, carrot, celery and olives, which add flavor to the soup as they cook, should be added first. More delicate ingredients like zucchini slices and cauliflower florets can be added toward the tail end. A cracked egg can be added after the heat has been turned off, to poach on the still-warm stove before serving time.
The herbs should be added by the eater, not the cook. For meat-based soups I like basil and cilantro, à la pho. Mint can be good as well, say, in a lamb soup. For a fish soup, consider dill or parsley. Tarragon is aromatic, but I avoid it, as even a small amount will take over the dish.
There are many other fragrant plant materials, though technically not herbs, that can also be added to the broth. They include green onions, a squirt of lime, sliced jalapeños, shredded raw garlic and fish sauce, all of which are added to pho—sliced jalapeños being an American addition that has become a ubiquitous part of the pho here.
Hoisin sauce, traditionally used in pho, is worth a squirt, as is Sriracha-style chili garlic sauce. Mayo, while neither fragrant nor typically added to pho, makes a great addition, too, if you ask me. And if you want noodles, by all means add them, but go easy on the veggies, or it might get too busy.
I'll leave the blanks to be filled in as you wish. But the basic formula is simple: Start with a savory broth, and then pho it up from there. With herbs.