Vietnamese Oxtail Pho: A Rich, Slow-Simmered Recipe

Vietnamese oxtail pho is a bowl of rice noodles and tender, bone-in beef served in a clear, aromatic broth flavored with charred onion, ginger, and warm spices. This home-style version simmers slowly for a rich beef flavor, then finishes with fresh herbs, lime, and other pho-table garnishes; seasoning and toppings vary from cook to cook.

Ingredients

4½ lb (2 kg) bone-in oxtail, cut into segments
14 cups (3.3 L) cold water, plus extra for blanching
2 large yellow onions, about 1 lb (450 g) total, halved
1 large piece fresh ginger, 5 oz (140 g), split lengthwise
4 whole star anise
1 cinnamon stick, about 3 inches (7.5 cm)
4 whole cloves
1 tablespoon (7 g) coriander seeds
1 teaspoon (2 g) fennel seeds
1 black cardamom pod, lightly cracked; optional
2 tablespoons (30 ml) fish sauce, plus more to taste
1 tablespoon (12 g) rock sugar or light brown sugar
1½ teaspoons (9 g) fine salt, plus more to taste
1 lb (450 g) dried flat rice noodles, medium width
4 scallions, about 2 oz (55 g), thinly sliced
1 small white or yellow onion, about 5 oz (140 g), thinly sliced
2 cups (60 g) loosely packed Thai basil leaves
2 cups (60 g) loosely packed cilantro leaves and tender stems
2 cups (60 g) bean sprouts
2 limes, cut into wedges
2 Thai bird’s-eye chiles, thinly sliced, or 1 jalapeño, thinly sliced
Hoisin sauce and chili sauce, for serving, optional

Instructions

Prepare the ingredients. Trim away any loose, thick pieces of surface fat from the oxtail, but leave the meat and connective tissue attached to the bones. Rinse the pieces under cold running water and pat them dry. Halve the onions, split the ginger, measure the spices, and slice the garnishes. Allow about 35 minutes for this prep, including organizing the ingredients.
Blanch and rinse the oxtail. Put the oxtail in a large stockpot and cover with cold water. Bring it to a boil over high heat and boil for 10 minutes; gray foam and residue will rise to the surface. Drain the oxtail and discard the blanching water. Rinse the pot and rinse each piece of oxtail under cool water, rubbing off any visible residue. This first boil is not the soup broth: discarding it helps the finished broth taste cleaner and look clearer.
Char the onion and ginger. While the oxtail blanches, heat a dry cast-iron skillet or heavy pan over medium-high heat. Set the onion halves and ginger cut-side down in the pan and char them for about 10 minutes, turning as needed so the cut surfaces brown in spots. They should smell toasted, not burnt through. A few dark patches add depth; black, acrid surfaces can make the broth bitter. Transfer the aromatics to a plate.
Toast the spices. Add the star anise, cinnamon, cloves, coriander, fennel, and optional black cardamom to the dry pan. Toast for about 2 minutes, shaking the pan often, just until fragrant. Put the spices in a spice bag or tie them loosely in a piece of clean cheesecloth. Keeping them together makes it easier to remove them before serving. If you do not have either, add them directly and strain the broth carefully later.
Start the broth. Return the rinsed oxtail to the clean stockpot and add 14 cups (3.3 L) cold water, the charred onion and ginger, and the spice bundle. Bring the pot slowly to a gentle simmer over medium-high heat, skimming foam from the surface as it appears. Once small bubbles rise steadily, lower the heat. Avoid a hard rolling boil, which can break up fat and cloud the broth.
Simmer until tender. Partially cover the pot and maintain a quiet simmer for 3 hours 35 minutes, checking every 30 to 45 minutes. Skim excess foam or a heavy layer of fat, and add a little hot water if the oxtail becomes exposed. The meat should be very tender and beginning to pull from the bones. USDA FSIS lists 145°F (63°C) with a 3-minute rest as the safe minimum for whole cuts of beef; check a meaty piece with a food thermometer, then allow at least 3 minutes of rest before handling. Continue simmering beyond that minimum until the oxtail is fork-tender.
Season and strain. Lift the oxtail onto a plate and let it rest while you strain the broth through a fine-mesh sieve into a clean pot. Discard the spices, onion, and ginger. Skim fat from the broth’s surface, leaving a little for flavor if you like. Stir in the fish sauce, sugar, and salt. Bring the broth back to a gentle simmer for about 10 minutes, then taste it. It should be savory and aromatic, with enough salt to season the noodles; add fish sauce or salt a little at a time if needed.
Cook the noodles and assemble. Prepare the rice noodles according to their package directions, since brands and widths differ. For many dried flat noodles, this means soaking or boiling briefly, then draining and rinsing; do not leave them in hot water after they turn tender. Divide the noodles among six large bowls. Pull the oxtail meat from the bones, discarding loose bone fragments, and divide the meat among the bowls. Ladle very hot broth over the noodles and beef, then top with sliced scallions and onion. Set out the herbs, bean sprouts, lime, chiles, and sauces so everyone can finish their own bowl.

Tips

Keep the broth at a simmer. A few small bubbles are enough. A rolling boil can emulsify fat into the liquid, making the broth cloudy and greasy. Skim gently rather than stirring the pot vigorously.
Use a spice bag if possible. It makes straining simpler and keeps small seeds out of the bowls. If black cardamom is unavailable, leave it out rather than replacing it with green cardamom; green cardamom tastes sweeter and more floral. The broth will still be fragrant without either.
Adjust the broth after straining. Oxtail varies in richness, and fish sauce brands vary in saltiness. Add the fish sauce and salt gradually, tasting before each addition. Rock sugar gives a mild, rounded sweetness; light brown sugar works as a practical substitute, with a slightly more molasses-like note.
Cook noodles close to serving. Rice noodles continue absorbing liquid and can turn soft if they sit in the broth. Keep cooked noodles separate until the bowls are assembled, and serve the broth hot enough to warm the meat and noodles.

Serving Suggestions

Serve the pho as soon as the bowls are assembled, with a platter of basil, cilantro, bean sprouts, lime wedges, and sliced chiles at the table. Diners can add herbs and sprouts to taste, then squeeze in lime for freshness. Hoisin and chili sauce are optional; offer them on the side so each person can choose how sweet or spicy to make the broth. For a more composed bowl, add only a small spoonful of sauce directly to the soup, since a generous amount can cover the oxtail and spice flavors.

This is a filling main course, so simple accompaniments work well. A small plate of sliced cucumber or a light vegetable side adds crunch without competing with the broth. If you are serving a group, keep extra hot broth in a covered pot and the garnishes separate. That way, people can build bowls as they sit down, and the noodles are less likely to soften while everyone waits.

Variations

Make it less rich: Chill the strained broth until the fat firms on top, then lift off as much as you prefer. This takes additional time, so it is best done when preparing the broth ahead. Some fat contributes flavor, so removing all of it is a matter of preference.

Use another beef cut: Beef shank or short ribs can replace some or all of the oxtail. Choose bone-in pieces for a broth with similar depth, and simmer until the meat is tender; timing will vary with the size and cut. A boneless chuck roast can also work, though the broth will have less gelatinous body. Check doneness with a thermometer and use tenderness, not the clock alone, to decide when the meat is ready.

Change the spice balance: For a gentler anise flavor, use three star anise instead of four. For a more warming broth, add a second small cinnamon stick. Keep the overall spice quantity restrained so the oxtail remains the main flavor. Pho recipes vary, and adjusting the spice balance is a practical way to suit your table.

Make it gluten-free: Rice noodles are naturally gluten-free, but check the package label and choose fish sauce and any optional condiments that are labeled gluten-free. For a lighter garnish, skip the sauces and use extra lime, herbs, and chiles instead.

Storage and Reheating

For best texture, store the broth and oxtail separately from the cooked noodles and fresh garnishes. Refrigerate leftovers within 2 hours in shallow, covered containers. The broth and meat keep for 3 to 4 days in the refrigerator; cooked noodles are best used within 2 days because they soften as they sit. If the broth has been chilled, a layer of solidified fat may form on top. Lift off some or all of it before reheating, according to your preference.

Reheat only the portion you plan to eat. Warm the broth and oxtail in a saucepan over medium heat until steaming, stirring occasionally; use a food thermometer to confirm leftovers reach 165°F (74°C). Add freshly cooked noodles to bowls and pour the hot broth over them. Previously cooked noodles can be briefly dipped in hot water to loosen them, then drained, but avoid simmering them in the broth.

For longer storage, freeze cooled broth and oxtail in airtight freezer-safe containers for up to 3 months for best quality. Leave a little room at the top for expansion. Thaw overnight in the refrigerator and reheat to 165°F (74°C). Freeze noodles separately only if necessary; their texture may be softer after thawing. Do not leave the soup at room temperature to cool for more than 2 hours.

Frequently Asked Questions

Can I make the broth a day ahead?
Yes. Cook and strain the broth, then refrigerate it with the oxtail in a covered container. The next day, remove any firm fat you do not want, reheat the broth and meat to 165°F (74°C), and cook or prepare the noodles just before serving. Add the fresh herbs and other garnishes at the table.

Why is my pho broth cloudy?
The most common causes are a vigorous boil, stirring too much, or leaving residue on the oxtail after blanching. Keep the broth at a gentle simmer, skim foam as it rises, and strain it through a fine-mesh sieve. A cloudy broth is still suitable to eat; it is mainly a difference in appearance and texture.

Do I have to blanch the oxtail?
Blanching is recommended for this recipe because oxtail can release blood and residue that would otherwise cloud the broth. Boil the pieces for 10 minutes, discard that water, and rinse both the meat and pot before starting the soup. Do not use the blanching water as part of the finished broth.

Can I use a slow cooker?
You can, but first blanch and rinse the oxtail, char the aromatics, and toast the spices as directed. Transfer them to the slow cooker with the water, then cook on low until the meat is very tender; slow cookers vary, so allow roughly 8 to 10 hours and check the texture. Strain and season the broth on the stove, and cook noodles separately.

What if I cannot find rock sugar or Thai basil?
Use light brown sugar in place of rock sugar, starting with the amount listed and adjusting after tasting. Thai basil has a distinctive anise-like aroma; ordinary sweet basil is an acceptable substitute but gives a softer, less peppery flavor. If neither is available, serve extra cilantro and lime rather than leaving out all the fresh garnish.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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