These mashed potatoes are made in the Instant Pot, which gets the potatoes cooked and ready to mash in 10 minutes of pressure time — no babysitting a pot of boiling water. The real difference-maker is freshly grated Pecorino Romano folded in at the end: it adds a sharp, salty depth that plain mashed potatoes just don’t have. Six ingredients, 30 minutes total, and the result holds up whether you’re feeding four on a Tuesday or a table full of guests.
The technique that matters
Two things determine whether mashed potatoes are creamy or gluey. First, size consistency: if your potatoes are uneven, the smaller ones overcook before the larger ones are done. Cut anything bigger than about 6 oz in half so everything finishes at the same time. Second, stop mashing the moment the butter is incorporated and the lumps are gone. Every extra stroke works the starch and tightens the texture. When you fold in the cream and Pecorino, use a spatula — not the masher — and fold gently. The mixture will look loose at first. Give it 60 seconds and it tightens up as the cheese melts and the starch absorbs the cream. Trust the process and put the masher down.
Substitutions that actually work
- Pecorino Romano: The recipe card notes Parmesan as a swap, and it works well. If you want to stay closer to the original sharp, salty flavor, use the best Pecorino you can find and grate it fresh — pre-shredded won’t melt as smoothly.
- Heavy cream: Half-and-half will work in a pinch, but the potatoes will be noticeably less rich. Avoid milk entirely; it makes the texture watery.
- Butter: European-style butter like Kerrygold has a higher fat content and makes a real difference here. Standard unsalted butter still produces a good result, but skip the margarine — the fat ratio is wrong for this recipe.
- Russet potatoes: Russets are the right call. Their high starch content is what gives you that fluffy, absorbent base. Waxy potatoes like red or Yukon Gold will produce a denser, stickier mash.
If something goes sideways
- Potatoes are still firm after pressure cooking: Reseal the lid, set to High pressure for 2 more minutes, and quick-release again. This usually happens when potatoes were very large or cold from the fridge.
- Mash is too thick: Add warm cream one tablespoon at a time, folding gently between additions. Cold cream added all at once can seize the starch and make the texture uneven.
- Mash is too thin: Let it sit uncovered for 2 to 3 minutes — the starch continues to absorb liquid as it cools slightly. If it’s still loose, a small knob of cold butter folded in will help bind it.
- Cheese clumped instead of melting: This happens when the potatoes are not hot enough when the cheese goes in. Transfer the potatoes immediately after mashing and fold the cheese in while everything is still steaming hot.
- Keeping a large batch warm without drying out: Skip the garnish — not worth the extra dish. Instead, press a sheet of plastic wrap directly onto the surface of the potatoes before putting the slow cooker lid on. It stops a skin from forming and keeps moisture in for up to two hours.
Storage and reheating
Leftovers keep in an airtight container in the fridge for up to 3 days. To reheat, put the potatoes in a saucepan over low heat and stir in a splash of heavy cream — start with two tablespoons per serving and add more as needed. Stir frequently and keep the heat low; high heat makes them gummy. For larger batches, the oven works well: spread the potatoes in a baking dish, add a few tablespoons of cream, cover tightly with foil, and warm at 325°F for about 20 minutes, stirring once halfway through. For freezing, portion into freezer bags, press flat, and freeze for up to 2 months. Thaw overnight in the fridge before reheating on the stovetop with cream as above — do not microwave from frozen, as the texture suffers significantly.
Super Creamy Mashed Potatoes (Instant Pot, 15 Min)
Equipment
- 6-quart Instant Pot or electric pressure cooker
- Steamer rack/trivet (included with most Instant Pots)
- Potato masher or potato ricer
- Large mixing bowl
- Silicone spatula
- Box grater or Microplane (for shredding Pecorino)
Ingredients
- 2 lbs russet potatoes peeled and left whole, about 900g
- 1 cup water for pressure cooker
- ¾ teaspoon kosher salt plus more to taste
- ¼ teaspoon freshly ground black pepper plus more to taste
- 4 oz unsalted butter cut into 1-inch cubes, about 115g / 1 stick (European-style such as Kerrygold recommended for best flavour)
- ½ cup Pecorino Romano cheese freshly grated, about 2 oz / 55g
- ½ cup heavy whipping cream about 120ml
Instructions
- Place a rack in the bottom of the pressure cooker. Add 1 cup of water.1 cup water
- Place peeled whole potatoes on top of the rack. If any potato is larger than a medium (about 6 oz / 170g), cut it in half so all pieces cook evenly. Place the lid onto your pressure cooker, locking it into place. Set the valve to sealing, pressure to High, and the timer to 10 minutes.2 lbs russet potatoes
- When the timer beeps, turn off the keep-warm function. Carefully move the steam release valve to the venting position to quick-release the pressure. Keep hands and face away from the steam vent.
- When the pressure is completely released, carefully open the lid. Using tongs or a slotted spoon, transfer the potatoes to a large mixing bowl (discard the cooking water). Add salt, pepper, and butter. Mash with a potato masher or potato ricer until smooth and the butter is fully melted.2 lbs russet potatoes, 3/4 teaspoon kosher salt, 1/4 teaspoon freshly ground black pepper, 4 oz unsalted butter
- Gently fold in the heavy cream and grated Pecorino Romano using a silicone spatula. The mixture may look runny at first, but it will thicken as the cheese melts and the starches absorb the cream. Fold just until combined — overworking will make the potatoes gluey.1/2 cup Pecorino Romano cheese, 1/2 cup heavy whipping cream
Notes
Nutrition
Frequently asked questions
Can I make these for a crowd and double or triple the recipe?
Yes, but do not exceed the max fill line on your Instant Pot — for a 6-quart model, 3 lbs of potatoes is a safe upper limit for one batch. For larger amounts, cook in two batches and combine in a big bowl to mash together, which takes only a few extra minutes and keeps the texture consistent.
Do I really need to peel the potatoes, or can I leave the skins on?
Peel them for this recipe. The skins break up unevenly during mashing and give you a chunky, inconsistent texture rather than a smooth one. If you want skin-on mashed potatoes, that’s a different recipe with a different technique.
Can I use a hand mixer instead of a masher or ricer?
Avoid it. A hand mixer overworks the starch almost instantly and turns the potatoes into a dense, paste-like texture. A masher or ricer gives you control over when to stop, which is the whole point.
My Instant Pot is an 8-quart — does the timing change?
Keep the pressure cooking time the same at 10 minutes on High. An 8-quart pot takes a few minutes longer to come to pressure because of the larger cavity, so your total time will be slightly longer, but the potatoes themselves cook at the same rate once pressure is reached.
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