Instant Pot Lentils and Celery Root Pasta

Instant Pot Lentils and Celery Root Pasta is one of those recipes that sounds like a stretch on paper — lentils and pasta together, plus a root vegetable most people walk past at the grocery store — and then turns out to make complete sense the moment you taste it. The lentils cook down soft and a little creamy in the Instant Pot, celery root brings a mellow, almost nutty flavor that’s nothing like the ugly knobby exterior suggests, and the pasta ties it all into something that eats like a proper dinner, not a side dish pretending to be one.

This is a genuinely good weeknight option if you’ve got an Instant Pot sitting on the counter and want something that doesn’t need much babysitting. Most of the work happens under pressure while you do something else.

Why This Recipe Is Worth Making

Lentils cook fast under pressure — no soaking, no hours on the stove — and they add real protein and body to a pasta dish without needing meat. Celery root, once you get past peeling it, cooks down soft enough to half-melt into the sauce, giving the whole thing a rounder, more savory backbone than tomato or cream alone would provide. It’s also a solid pantry-plus-produce-drawer meal: dried lentils keep for ages, and celery root keeps for weeks in the fridge, so this is a good one to have in your back pocket when you haven’t shopped in a few days.

What You’ll Need

• 1 cup dried green or brown lentils, rinsed
• 1 medium celery root (about 1 lb), peeled and diced into 1/2-inch cubes
• 2 tablespoons olive oil
• 1 small yellow onion, diced
• 3 garlic cloves, minced
• 3 cups vegetable broth
• 8 oz short pasta (shells or orecchiette work well)
• 1/2 cup grated Parmesan, plus more for serving
• 1 tablespoon lemon juice
• Salt and black pepper, to taste
• Fresh parsley, chopped, for serving

A note on celery root: Also called celeriac, it looks intimidating — a rough, hairy, knobby exterior that doesn’t resemble anything you’d want to eat. Cut off the outer layer with a sharp knife rather than a peeler, going about 1/4 inch deep to get past the tough, fibrous skin. Underneath, it’s pale and firm, with a flavor that’s part celery, part potato, part parsley. If you can’t find it, parsnips are the closest substitute in both texture and how they behave under pressure, though the flavor will lean sweeter and less savory. Green or brown lentils hold their shape better than red lentils here — red lentils cook down to mush fast and will turn this into more of a stew than a pasta dish, so stick with green or brown for the texture this recipe wants.

How to Make It

1. Set the Instant Pot to Sauté and add the olive oil. Once it’s shimmering, add the onion and cook for 3 minutes, stirring occasionally, until it softens and turns translucent.
2. Add the garlic and cook for 30 seconds, just until fragrant — don’t let it sit still, since garlic burns fast on the pot’s residual heat.
3. Add the rinsed lentils, diced celery root, and vegetable broth. Give everything a good stir, making sure there’s no browned bits stuck to the bottom of the pot — those can trigger a burn warning during pressure cooking, so scrape the bottom clean if needed.
4. Cancel the Sauté function, seal the lid, and set the valve to sealing. Select Pressure Cook (or Manual) on high for 8 minutes.
5. Once the cook cycle ends, let the pressure release naturally for 10 minutes, then manually release any remaining pressure. This slower release matters here — venting immediately can cause the lentils’ cooking liquid to sputter out through the valve.
6. Open the lid. The lentils should be tender but still holding their shape, not mushy, and the celery root should be soft enough to pierce easily with a fork. If either needs more time, seal the lid again and cook on high pressure for another 2 minutes.
7. Set the Instant Pot back to Sauté. Add the pasta directly to the pot along with enough water to just cover it, about 1 to 1 1/2 cups depending on how much liquid remains. Simmer, stirring occasionally, for 8 to 10 minutes, until the pasta is al dente and most of the liquid has absorbed into a light, clingy sauce.
8. Stir in the Parmesan and lemon juice. Taste and season with salt and pepper — the broth and cheese both carry some salt already, so add gradually. Serve topped with parsley and extra Parmesan.

Tips That Actually Make a Difference

• Cut the celery root into pieces roughly the same size as your lentils’ cooking behavior needs. Too large and it won’t fully soften in 8 minutes; too small and it can disintegrate. Half-inch cubes are the sweet spot.
• Scrape the bottom of the pot thoroughly after sautéing the onion and garlic. Any stuck bits can trigger the Instant Pot’s burn protection sensor and stop the cooking cycle before it starts.
• Add the lemon juice at the very end, off heat. It brightens the whole dish, and adding it too early means the flavor cooks off instead of staying sharp on the palate.
• Don’t skip the natural release. Venting immediately after pressure cooking with this much liquid in the pot can cause a genuinely messy sputter through the valve.

Mistakes to Watch Out For

• Using red lentils instead of green or brown. Red lentils break down almost completely under pressure, and you’ll end up with more of a thick stew than a pasta dish with texture. Stick with green or brown lentils.
• Not peeling the celery root deeply enough. The outer layer is tough and fibrous — a light peel leaves bits of that behind, which stay chewy even after cooking. Cut in about 1/4 inch with a knife rather than relying on a vegetable peeler.
• Skipping the burn-warning check. If your Instant Pot flashes a burn notice, it’s picking up on stuck food at the bottom. Cancel, scrape the pot clean, and add a splash more liquid before restarting.
• Adding all the pasta water at once without checking consistency. Start with the lower end of the water range and add more only if the pasta looks dry — too much liquid and you’ll end up with soup instead of a clingy sauce.

Easy Ways to Change It Up

• Add a handful of baby spinach at the very end, stirring it in until wilted — it adds color and a mild vegetable note without much extra effort.
• Swap Parmesan for Pecorino Romano if you want a sharper, saltier finish; use slightly less since Pecorino tends to be more assertive.
• Make it vegan by using nutritional yeast in place of Parmesan and skipping straight to the lemon juice for brightness — it won’t taste identical, but it holds up well.
• Add red pepper flakes with the garlic if you want some heat running through the dish; start with a pinch and adjust from there.

What to Serve It With

This is filling enough to stand as a full meal on its own, but a simple arugula salad with a sharp lemon vinaigrette on the side adds some peppery contrast to the softer, rounder flavors in the bowl. Crusty bread is good for anyone who wants to mop up the last bit of sauce. If you want to round it out further for a crowd, roasted broccoli or Brussels sprouts on the side keep things in the same comfort-food register without adding much extra work.

Leftovers and Reheating

Store leftovers in an airtight container in the fridge for up to 4 days. Reheat gently in a skillet over medium-low heat with a splash of water or broth to loosen the sauce, which thickens considerably once cold. The microwave works fine here too — just add a little liquid first and stir halfway through so it heats evenly instead of drying out at the edges. This dish also freezes reasonably well for up to 2 months, though the celery root’s texture softens further on thawing; that’s a minor tradeoff and doesn’t really hurt the finished dish.

Approximate Nutrition Per Serving

These numbers are estimates only, based on standard ingredient data, and will vary depending on the specific brands and portion sizes you use.

Final Thoughts

Instant Pot Lentils and Celery Root Pasta is worth making because it turns two ingredients that don’t usually get much attention — dried lentils and an ugly root vegetable — into something that eats like a real, satisfying dinner with almost no active effort involved. If you’ve got a bag of celery root you weren’t sure what to do with, this is a genuinely good answer.