Air Fryer Lentil Soup
The secret to a lentil soup that tastes like it simmered all afternoon isn't time — it's a fast, aggressive roast. Here the classic trio of carrot, onion, and celery gets a quick trip through the air fryer until the edges caramelize and the sugars concentrate, which builds the kind of browned, savory depth you'd normally spend twenty minutes coaxing out of a stovetop sauté. That roasted base gets scraped into a pot with green lentils, fire-roasted tomato, and a warm spice blend, then simmers until the lentils are just tender — not falling apart. The point of this one isn't subtlety, it's the numbers: a bowl that stacks roughly equal parts fiber and protein without a scrap of meat, which is exactly why "fiber is the new protein" has become this fall's loudest food mantra. Lentils are a prebiotic powerhouse — the soluble fiber in each bowl feeds the good bacteria in your gut while the insoluble fiber keeps everything moving — and pairing them with roasted aromatics makes the whole thing taste a lot more indulgent than it is. It's the cozier cousin to our Air Fryer Roasted Vegetables, and a natural follow-up to Butternut Squash Soup for anyone chasing a more protein-forward bowl.
Dinner · Vegan, Gluten-Free, Fall, High-Fiber, High-Protein • 50 min
Nutrition (per serving)340Calories·9gFat·50gCarbs·18gProtein
Per serving. Values are approximate and calculated from USDA FoodData Central.
Ingredients
- For the air-fryer roasted base:
- 3 medium carrots, peeled and cut into 1-inch chunks
- 1 large yellow onion, cut into 1-inch wedges
- 3 celery stalks, cut into 1-inch pieces
- 4 garlic cloves, smashed
- 3 tablespoons olive oil, divided
- 1¾ teaspoons kosher salt, divided, plus more to taste
- For the soup:
- 1½ cups dried brown or green lentils, picked over and rinsed
- 2 tablespoons tomato paste
- 2 teaspoons ground cumin
- 1 teaspoon smoked paprika
- 1 teaspoon dried thyme (or 3 sprigs fresh)
- 1 bay leaf
- 1 (14.5-ounce) can canned fire-roasted diced tomatoes
- 6 cups low-sodium vegetable broth
- 2 cups baby spinach or chopped kale
- 1 tablespoon fresh lemon juice
- freshly ground black pepper, to taste
- For serving (optional):
- chopped fresh parsley or cilantro
- toasted pepitas or crusty bread
- optional protein add-in (see headnote): shredded rotisserie chicken, crumbled feta, a dollop of Greek yogurt, or crispy roasted chickpeas
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Steps
- Heat the air fryer to 400°F. In a large bowl, toss the carrots, onion, celery, and garlic with 2 tablespoons of the olive oil and ½ teaspoon of the kosher salt until evenly coated.
- Air-fry the vegetables: Arrange the vegetables in the air-fryer basket in a single layer (work in batches if your basket is crowded — overcrowding steams instead of roasts). Cook, shaking the basket halfway through, until the edges are deeply browned and the carrots are just tender, 14 to 18 minutes.
- Bloom the aromatics: Meanwhile, heat the remaining 1 tablespoon olive oil in a large Dutch oven or heavy pot over medium heat. Add the tomato paste, cumin, smoked paprika, and thyme and cook, stirring constantly, until the paste darkens a shade and the spices smell toasted, 1 to 2 minutes.
- Combine: Scrape in the roasted vegetables, then add the lentils, fire-roasted tomatoes with their juices, bay leaf, the remaining 1¼ teaspoons kosher salt, and the vegetable broth. Stir to combine and bring to a boil over high heat.
- Simmer: Reduce the heat to a gentle simmer, partially cover, and cook, stirring occasionally, until the lentils are just tender but still hold their shape, 25 to 30 minutes. Skim any foam that rises to the surface.
- Finish: Remove the bay leaf. Stir in the spinach and cook just until wilted, 1 to 2 minutes. Off the heat, stir in the lemon juice and season generously with black pepper and more salt to taste.
- Serve: Ladle into bowls and finish with parsley, a scatter of pepitas, or any optional protein add-in.
Tips & Variations
Make Ahead
This soup only improves overnight — the roasted base mellows and the lentils drink up the broth. Cool completely and refrigerate for up to 4 days. If it thickens in the fridge (lentils keep absorbing liquid), loosen it with a splash of broth or water when you reheat. It also freezes beautifully: portion it out and freeze for up to 3 months, then thaw and reheat gently.
Storage
Refrigerate in an airtight container for up to 4 days, or freeze in portions for up to 3 months. Reheat over medium-low heat, stirring and adding broth as needed, until warmed through. The greens will soften on reheating — that's expected; a squeeze of fresh lemon at the table brings it back to life.
Substitutions
Red lentils cook faster but dissolve into a creamier, thicker soup — use them if you want a more porridge-like texture, and cut the simmer to 15 to 20 minutes. French green lentils (lentilles du Puy) hold their shape best if you prefer a soupier bowl. No air fryer? Roast the vegetables on a sheet pan at 450°F for 20 to 25 minutes instead. Swap the spinach for any sturdy green — kale, chard, or even frozen chopped spinach squeezed dry. For extra protein, stir in a can of drained white beans during the last 5 minutes, top each bowl with shredded rotisserie chicken or crumbled feta, or swirl in Greek yogurt; keep it fully plant-based with crispy roasted chickpeas.
Nutrition
Per serving: ⅙ of the recipe (about 1½ cups)
Reviews
Reviews coming soon! In the meantime, let us know what you think of this recipe.
