How Long to Cook Flanken Ribs in the Oven

Flanken ribs are beef short ribs sliced thinly across the bones, so each piece has several small bone sections and ribbons of meat. This recipe braises them covered in a savory soy, garlic, and beef-broth sauce; the low oven and moist heat make the meat tender without drying it out.

Ingredients

3 lb (1.36 kg) flanken-cut beef short ribs, about ½–¾ inch (1–2 cm) thick
1 tsp (6 g) fine salt
½ tsp (1 g) ground black pepper
1 tbsp (15 ml) neutral oil, such as canola or avocado oil
1 medium yellow onion, about 1 cup (150 g) chopped
4 garlic cloves, about 1 tbsp (15 g) finely chopped
1½ cups (355 ml) low-sodium beef broth
¼ cup (60 ml) low-sodium soy sauce
2 tbsp (30 ml) rice vinegar
1 tbsp (12 g) packed brown sugar
1 tsp (2 g) sweet paprika
2 tsp (6 g) cornstarch (optional, for thickening the sauce)
1 tbsp (15 ml) cold water (optional, to mix with the cornstarch)
2 tbsp (6 g) sliced scallions and 1 tsp (3 g) toasted sesame seeds, for serving (optional)

Instructions

Heat the oven and prepare the ribs. Set a rack in the middle of the oven and heat it to 300°F (150°C). Pat the ribs dry with paper towels. If there are large, loose flaps of fat, trim those away, but leave a thin layer in place for flavor. Season both sides with the salt and pepper. Have a deep, oven-safe Dutch oven or roasting pan with a tight-fitting lid ready; the ribs should fit in a mostly even layer.
Brown the meat. Heat the oil in the Dutch oven over medium-high heat until it shimmers. Working in batches so the pan is not crowded, brown the ribs for about 1–2 minutes per side, just until the surfaces take on color. The ribs will not be cooked through at this point. Transfer them to a plate. If the pan looks dry between batches, add a small splash of oil; if there are browned bits on the bottom, leave them there for the sauce.
Make the braising liquid. Lower the heat to medium. Add the chopped onion and cook for 3–4 minutes, stirring, until it starts to soften. Stir in the garlic and paprika and cook for about 30 seconds, just until fragrant. Pour in the beef broth, soy sauce, rice vinegar, and brown sugar. Scrape the bottom of the pan with a wooden spoon to loosen the browned bits, then bring the liquid to a gentle simmer. If you are using a roasting pan rather than a Dutch oven, make the sauce in a skillet and pour it into the pan.
Cover and braise. Return the ribs to the pan, arranging them as snugly as possible with the meaty sides partly exposed above the liquid. Cover with the Dutch oven lid. For a roasting pan, cover it tightly with heavy-duty foil, crimping the edges so steam stays inside. Bake for 2 hours and 15 minutes. The sauce should bubble gently, not boil vigorously. If it is boiling hard, lower the oven temperature slightly; strong boiling can make the meat tighten and the liquid evaporate too quickly.
Check for safety and tenderness. Carefully uncover the pan, keeping your face away from the steam. Check the thickest meaty section with a food thermometer without touching a bone: USDA FSIS gives 145°F (63°C) followed by a 3-minute rest as the safe minimum for whole cuts of beef. For the tender, braised texture, the meat should also yield easily when pressed with a fork. If it is still firm, cover the pan again and bake in 15-minute increments until tender; thicker pieces and ovens that run cool may need extra time.
Rest and finish the sauce. Lift the ribs onto a warm platter and let them rest for 10 minutes. Skim excess fat from the surface of the sauce if you like. For a thicker sauce, mix the cornstarch with the cold water until smooth, bring the liquid to a simmer on the stovetop, and stir in the slurry. Simmer for 1–2 minutes, until glossy and lightly thickened. Spoon sauce over the ribs and finish with scallions and sesame seeds, if using.

Tips

Check the cut before setting the timer. Flanken ribs are cut across the bones and are usually much thinner than English-cut short ribs, which are cut into thick sections. This recipe’s oven time suits ribs about ½–¾ inch thick. If yours are closer to 1 inch (2.5 cm), expect to add time and judge by tenderness rather than relying on the clock alone.
Keep the pan covered. The tight lid or foil traps moisture and is central to this braising method. A loose cover lets liquid evaporate and can leave the upper surfaces dry. If the ribs are not quite submerged, that is fine; they steam above the sauce while the lower portions braise.
Use an easy soy-sauce swap if needed. Tamari can replace soy sauce in the same quantity and gives a similar savory flavor. Coconut aminos are milder and sweeter, so reduce the brown sugar or add it gradually and taste the sauce. If using regular, full-sodium broth or soy sauce, reduce or omit the added salt until you taste the finished liquid.
Do not confuse safe with tender. The thermometer confirms a safe minimum, while fork tenderness tells you whether the connective tissue has softened enough for a braised result. A rib can be safe to eat but still chewy; return it to the oven, covered, rather than increasing the heat sharply.

Serving Suggestions

Serve the ribs with plenty of sauce over steamed rice, mashed potatoes, or buttered egg noodles, all of which catch the savory cooking liquid. For a lighter plate, add roasted carrots, sautéed cabbage, green beans, or a crisp cucumber salad dressed with rice vinegar. The ribs are rich, so a bright, crunchy side balances the meal well. Put extra sauce on the table, and offer scallions or sesame seeds for anyone who wants a little more color and texture.

If serving from the braising pan, use tongs or a wide spatula because the meat may be tender enough to separate from the bones. Warn diners that each flanken piece contains several bone cross-sections. For a family-style meal, arrange the ribs in a shallow platter and spoon just enough sauce over them to coat; keep the rest warm separately so the meat does not sit in a deep pool and become difficult to serve.

Variations

Ginger and pear: Add 1 tbsp (6 g) grated fresh ginger with the garlic. For a gentle sweetness common in many Korean-style short-rib marinades, replace the brown sugar with ¼ cup (60 g) finely grated Asian pear. If Asian pear is hard to find, use a ripe Bosc pear; it gives a slightly softer, less crisp fruit note. The fruit adds sweetness, so taste the sauce before adding any extra sugar.

More heat: Add ½–1 tsp (1–2 g) red-pepper flakes to the onion and garlic, or serve chili sauce at the table. This keeps the base batch mild and lets diners adjust their own portions. For a smoky variation, replace the sweet paprika with smoked paprika; use the same amount, as too much can overpower the broth and beef.

Oven-roasted finish: If you prefer browned edges, transfer the cooked ribs to a foil-lined baking sheet after they become tender. Brush lightly with reduced sauce and broil briefly, watching closely so the sugars do not burn. This is an optional finishing step, not a replacement for the covered braise: flanken ribs need the moist oven time first to become tender.

Storage and Reheating

Refrigerate leftover ribs and sauce within 2 hours of cooking in a shallow, airtight container. They keep for 3–4 days in the refrigerator. Store the meat with some sauce so it does not dry out, and remove any bones only after cooking if that makes leftovers easier to pack. The sauce may thicken or turn slightly gelatinous when chilled; that is normal, and it loosens as it warms.

For the gentlest reheating, place the ribs and sauce in a covered oven-safe dish with a spoonful of broth or water if the sauce is very thick. Heat at 300°F (150°C) until hot throughout, turning or spooning sauce over the meat once if needed. You can also reheat individual portions in a covered saucepan over low heat. Reheat leftovers to 165°F (74°C), checking the meat with a food thermometer. Freeze portions in airtight freezer-safe containers for up to 2–3 months for best quality; thaw overnight in the refrigerator before reheating.

Frequently Asked Questions

How long do flanken ribs take in the oven?
For ribs about ½–¾ inch thick, plan on roughly 2 hours and 15 minutes covered at 300°F (150°C), after browning them on the stovetop. Include about 10 minutes to brown and 10 minutes to rest, so this recipe takes about 2 hours and 55 minutes from start to serving. Thickness, the pan, and oven accuracy all affect the time, so check tenderness and allow extra 15-minute oven intervals if necessary.

Can I cook flanken ribs at 350°F instead?
You can, but this recipe uses 300°F for a slower, gentler braise. At 350°F (175°C), the liquid will heat and evaporate faster, so keep the pan tightly covered and begin checking earlier, around 1 hour and 45 minutes. Continue until the ribs are fork-tender, adding a little hot broth if the pan is getting dry. The exact finish time depends on thickness, so do not use a higher temperature as a guarantee of a shorter cook.

Should flanken ribs be covered in the oven?
Yes, for this braised preparation. A lid or tightly crimped foil holds in steam and keeps the meat moist while the connective tissue softens. Uncovered cooking is better suited to a quick roast or broil of very thin ribs, which is a different method and produces a chewier, less saucy result. If you uncover the ribs only to brown them at the end, watch closely because the sauce contains sugar and can scorch.

What temperature should flanken ribs reach?
For whole cuts of beef, the USDA FSIS safe minimum is 145°F (63°C), followed by a 3-minute rest. Measure in the thickest part of the meat and avoid touching the bone, which can give a misleading reading. For this braised recipe, also look for meat that yields readily to a fork; the minimum temperature alone does not mean the ribs have reached a tender braised texture.

Can I put frozen flanken ribs straight in the oven?
Thaw the ribs before following this recipe. Frozen pieces will not brown properly, may cook unevenly in the covered pan, and make it harder to check the center accurately. Thaw them in the refrigerator, allowing enough time for the pieces to separate and soften, then pat them dry before seasoning. Do not thaw beef on the counter; if the ribs are still partly frozen, give them more refrigerator time rather than shortening the oven stage.

Why are my flanken ribs still tough after the listed time?
They may be thicker than the cut used for the recipe, or the oven may be running below its set temperature. Keep the pan covered and continue baking in 15-minute increments, checking for easy fork separation each time. Do not add a lot of extra liquid unless the pan is nearly dry; the ribs should braise gently, not boil. Once tender, rest them for 10 minutes and serve with the cooking sauce.

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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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