Instant Pot Lamb Shanks with Creamy Mashed Potatoes

Tender lamb shanks, a silky garlic-and-herb sauce, and a generous bed of buttery mashed potatoes—this is the kind of dinner that makes everyone happy to gather around the table. These Instant Pot lamb shanks look beautiful enough for a special occasion, but a few simple shortcuts make them so much easier to prepare.

My favorite? Brown the lamb under the broiler. Everything gets color at the same time while you get the vegetables started in the Instant Pot. If you’re cooking more than two or three shanks, this saves you from standing over the pot browning batch after batch.

And that sauce? We’re blending the softened vegetables right into it, then finishing with fresh lemon juice. It’s rich, smooth, and delicious spooned over the potatoes. You’ll want plenty on your plate.

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Why this works so well for entertaining

Each person gets a lamb shank over creamy potatoes, so even the plating is easy. The pressure cooker handles the long cooking, the potatoes simmer separately, and you can make the lamb a day ahead.

There’s no wine in this recipe. Broth, balsamic vinegar, garlic, herbs, and the lamb’s cooking juices create plenty of flavor. Blending the vegetables gives the sauce body without needing cream.

The equipment I use

I use my 8-quart Instant Pot for this recipe. It gives me room for four lamb shanks, and I use 2¾ cups of broth for this size pot.

You can also use another pressure cooker. Follow its minimum-liquid and maximum-fill requirements, and keep in mind that stovetop pressure cookers may need timing adjustments.

If you’re considering an Instant Pot, I think it’s worth the investment—especially if you enjoy making soups, stews, and tender lamb without hours of stovetop cooking.

For the sauce, I use this immersion blender. After removing the lamb, herbs, and excess surface oil, I blend the vegetables directly into the cooking liquid. It makes such a lovely sauce with very little extra work.

What you’ll need

Lamb shanks: Choose shanks of similar size, about 12–16 ounces each, so they cook more evenly. Plan on one per person.

Onion, carrot, celery, and garlic: These flavor the cooking liquid, then get blended into the finished sauce. There’s no need to strain away those delicious vegetables.

Tomato paste, cumin, and balsamic vinegar: Small amounts add depth and balance without overpowering the lamb.

Broth, rosemary, bay leaves, and oregano: These build the savory sauce. Low-sodium broth makes it easier to control the salt as the sauce cooks down.

Fresh lemon: The juice of half a lemon goes in near the end to brighten the sauce.

Potatoes, butter, and half-and-half: Yukon Gold or Russet potatoes both work well. I peel the potatoes and boil them whole in salted water, then mash them with butter and warm half-and-half.

Optional garlic for the potatoes: Sometimes I add two or three peeled whole garlic cloves to the boiling water with the potatoes. Once tender, they mash right in and give the potatoes a mild garlic flavor.

How to make Instant Pot lamb shanks

Brown the lamb under the broiler

Season the shanks and arrange them on a broiler-safe pan. Broil for 20 minutes total, flipping halfway through, until nicely browned. Watch them closely because broilers vary.

Meanwhile, soften the onion, carrot, and celery in the Instant Pot. Add the garlic, tomato paste, and cumin, then pour in some broth and scrape the bottom thoroughly.

Let the pressure cooker tenderize the lamb

Add the remaining broth, balsamic vinegar, rosemary, bay leaves, and browned shanks.

Cook on High Pressure for 50 minutes, followed by a 20-minute natural release, then release any remaining pressure. That’s the cooking cycle; allow additional time for the pot to come to pressure.

Boil and mash the potatoes

While the lamb cooks, simmer the peeled whole potatoes in salted water until a knife slides easily through the centers. Drain well, let excess moisture evaporate, and mash with butter and warm half-and-half.

Blend and finish the sauce

Carefully remove the tender lamb, discard the bay leaves and rosemary stems, and skim some of the excess oil from the top.

Add the oregano, then use an immersion blender to puree the vegetables into the sauce. Simmer uncovered for 10 minutes, stirring occasionally. Add the juice of half a lemon, taste for seasoning, and return the shanks to warm through.

Serve over a generous bed of mashed potatoes with sauce spooned over everything.

Questions and troubleshooting

Why are my lamb shanks still tough?

They usually need more time for the connective tissue to soften. A fork should slide easily into the thickest part, and the meat should begin pulling away from the bone.

If they’re still firm, check that sufficient liquid remains and cook for another 10–15 minutes on High Pressure, followed by a 10-minute natural release.

Do the shanks need to be submerged?

No. Use the specified broth quantity and keep everything below your cooker’s maximum fill line. The shanks can overlap as long as they fit comfortably and don’t interfere with the lid or valve.

Can I double the recipe?

Only if everything fits within your cooker’s capacity. Don’t automatically double the liquid or the pressure-cooking time. For a larger gathering, cooking separate batches ahead is easier than overcrowding the pot.

What if I get a burn warning or the pot won’t seal?

Make sure the sealing ring is seated correctly, the steam release is positioned according to your model’s instructions, and there’s enough thin cooking liquid.

For a burn warning, cancel cooking and follow the manufacturer’s instructions for safely releasing pressure. Once safe to open, check for scorched food on the bottom. Transfer the unburned contents, clean the pot, and restore sufficient liquid before restarting. Never force open a pressurized cooker.

Why is my sauce greasy or too thin?

Skim excess oil before blending so you don’t blend it back into the sauce.

Pureeing the vegetables adds body, and the uncovered simmer helps concentrate the sauce. If you’d like it thicker after 10 minutes, simmer a little longer, stirring frequently, or use the optional cornstarch slurry in the recipe card.

What if the sauce is too salty or lemony?

Taste before adding the final salt. If it’s too salty, loosen it with a little unsalted broth or water. Since lemons vary, stir in the juice gradually; you can always add more.

Can I use frozen lamb?

Thaw the shanks completely in the refrigerator first. This recipe’s broiling step and cooking time are written for thawed lamb.

How do I avoid watery or gluey mashed potatoes?

Cook the potatoes until tender all the way through, drain thoroughly, and let excess moisture evaporate before mashing. Add warm half-and-half gradually. Use a hand masher or ricer; a blender or food processor can make potatoes gluey.

Make-ahead, storage, and serving tips

For an easier dinner party: Prepare the lamb and sauce a day ahead. Cool promptly in shallow containers and refrigerate within two hours. Reheat gently, covered, with a splash of broth if needed, until thoroughly hot. Make the potatoes closer to serving.

For the table: A crisp green salad or simply cooked green vegetables balances the rich lamb and potatoes. Add bread for anyone who wants to enjoy every last bit of sauce.

For leftovers: Refrigerate lamb and potatoes separately for 3–4 days, keeping the lamb in its sauce. Reheat leftovers to 165°F. Warm potatoes gently with a little additional dairy to loosen them.

For the freezer: Freeze the lamb with its sauce for up to 3 months for best quality. Thaw overnight in the refrigerator before reheating. Potatoes can be frozen separately, though their texture may change.

More Instant Pot dinners you’ll love

For another comforting lamb dinner, try my Instant Pot Lamb Stifado with shallots and warming spices, or Lamb Fricassee in the Instant Pot with greens and egg-lemon sauce.

My Instant Pot Greek Chicken Youvetsi and Greek Lemony Chicken and Orzo Soup are wonderful choices for your next cozy family dinner.

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