Good Recipes Using Lentils: Spiced Lentil Soup

This tomato-spiced lentil soup combines brown or green lentils with carrots, celery, warm spices, and leafy greens in a satisfying one-pot meal. It is easy to adapt to the vegetables and broth you have, and a squeeze of lemon at the end brightens the earthy, savory flavor.

Ingredients

2 tablespoons (30 ml) olive oil
1 medium yellow onion, diced, about 1 cup (150 g)
2 medium carrots, diced, about 1 cup (150 g)
2 celery ribs, diced, about 1 cup (100 g)
4 garlic cloves, finely chopped, about 12 g
2 tablespoons (32 g) tomato paste
1½ teaspoons (3 g) ground cumin
1 teaspoon (2 g) ground coriander
1 teaspoon (2 g) smoked paprika
½ teaspoon (0.5 g) dried thyme
¼ teaspoon (0.5 g) red pepper flakes, optional
1½ cups (300 g) dried brown or green lentils, picked over and rinsed
1 can diced tomatoes, 14½ ounces (411 g), with their juices
6 cups (1.4 L) low-sodium vegetable broth or chicken broth
1 dried bay leaf
1 teaspoon (6 g) fine salt, plus more to taste
½ teaspoon (1 g) freshly ground black pepper
3 ounces (85 g) baby spinach, or chopped kale with tough stems removed
2 tablespoons (30 ml) fresh lemon juice, plus more to taste
¼ cup (15 g) chopped fresh parsley, for serving

Instructions

Prepare the lentils and vegetables. Spread the lentils on a plate or tray and remove any small stones or damaged lentils, then rinse them in a fine-mesh strainer under cool water. Dice the onion, carrots, and celery, and chop the garlic. This preparation takes about 15 minutes; brown or green lentils do not need to be soaked for this soup.
Soften the vegetables. Heat the olive oil in a large heavy-bottomed pot or Dutch oven over medium heat. Add the onion, carrots, and celery, and cook for 8 minutes, stirring every so often. The onion should look translucent and the vegetables should begin to soften, but they do not need to brown. If the pot seems dry or the onion is catching, lower the heat slightly.
Toast the aromatics. Add the garlic, tomato paste, cumin, coriander, smoked paprika, thyme, and optional red pepper flakes. Stir continuously for about 2 minutes, until the garlic smells fragrant and the tomato paste darkens slightly. Keep the heat moderate; scorched garlic or spices can make the broth taste bitter.
Add the lentils and simmer. Stir in the rinsed lentils, diced tomatoes and their juices, broth, bay leaf, salt, and black pepper. Raise the heat and bring the pot to a boil, which should take about 5 minutes. Lower the heat to maintain a gentle simmer, partially cover the pot, and cook for 32 minutes. Stir once or twice, scraping the bottom, and check near the end: tender lentils should hold their shape but be easy to bite. If they are still firm, simmer a few minutes longer and check again.
Finish the soup. Remove the bay leaf. Stir in the spinach and cook for about 2 minutes, just until wilted; if using kale, allow a few extra minutes until it is tender. Turn off the heat, add the lemon juice, and taste the broth. Add more salt, pepper, or lemon as needed. The cooking steps take about 50 minutes in total, including bringing the soup to a simmer.
Serve. Ladle into bowls and scatter parsley over the top. If the soup thickens while it sits, stir in a little hot water or broth until it reaches the consistency you like.

Tips

Choose brown or green lentils. They become tender while generally holding their shape, which gives the soup a hearty texture. Red lentils break down much faster and make a softer, thicker soup; if using them, start checking after about 15 minutes of simmering rather than following the full cook time.
Check the lentils before cooking. Dried lentils can contain small stones or bits of debris, so sorting them on a plate and rinsing them is worth the short effort. Older lentils sometimes take longer to soften, so use tenderness rather than the clock alone as your final guide.
Adjust the broth for your preferred texture. Six cups make a spoonable soup that thickens as it cools. For a looser, brothier bowl, add up to 1 cup (240 ml) extra broth or water near the end. For a thicker result, simmer uncovered for a few minutes, stirring so lentils do not stick.
Season in stages. Broths vary in saltiness, so start with the measured salt and adjust after the lentils are tender. Lemon juice also changes the balance: add it at the end, taste, and add more in small splashes rather than pouring in extra all at once.

Serving Suggestions

Serve the soup hot with crusty bread, toasted pita, or warm flatbread for dipping. A spoonful of plain yogurt or a drizzle of olive oil makes a simple topping; use a dairy-free yogurt if you want to keep the meal dairy-free. For a fuller spread, add a crisp green salad dressed with vinegar or lemon, since its fresh, sharp flavor pairs well with the rich lentils.

You can also serve the soup over a small scoop of cooked rice, bulgur, or couscous, especially if you prefer a more substantial bowl. Put extra lemon wedges, chopped parsley, and red pepper flakes on the table so everyone can season their own portion. If serving several people, keep the soup warm over low heat and stir occasionally; add a splash of broth if it thickens before dinner.

Variations

Make it smoky and spicy. Add another ¼ teaspoon red pepper flakes, or stir in a chopped fresh chile with the onion. For a deeper smoky flavor, use a little more smoked paprika, but keep the amount modest so it does not overpower the lentils and tomatoes.

Use different greens or vegetables. Chopped kale, chard, or collards can replace spinach; add sturdy greens early enough to soften, usually 5 to 10 minutes before the lentils are done. A diced red bell pepper can go in with the onion, carrots, and celery. Zucchini is another option, but add it during the last 10 minutes so it does not become mushy.

Change the spices. For a more Mediterranean-leaning bowl, use dried oregano instead of thyme and finish with extra parsley. A pinch of ground cinnamon can add warmth, while curry powder can replace the cumin, coriander, and paprika for a different flavor direction. These are flexible home-cooking variations, not fixed regional versions of a single traditional dish.

Make it creamy. Once the lentils are tender, blend one or two cups of soup and stir it back into the pot. This thickens the broth without adding cream and keeps some lentils whole for texture. For a completely smooth soup, blend carefully in batches and follow your blender manufacturer’s guidance for hot liquids.

Storage and Reheating

Let the soup cool briefly, then refrigerate it in shallow, covered containers within 2 hours of cooking. It keeps for 3 to 4 days in the refrigerator. The lentils absorb broth as they sit, so expect the soup to be thicker the next day; stir in water or broth when reheating to loosen it.

Reheat a portion in a saucepan over medium heat, stirring occasionally, until it is steaming throughout and reaches 165°F (74°C). In a microwave, cover the bowl loosely, heat in short intervals, and stir between intervals so there are no cool spots; check that it reaches 165°F (74°C). Heat only the amount you plan to eat rather than repeatedly warming the whole batch.

For longer storage, freeze cooled soup in freezer-safe containers, leaving a little room at the top for expansion. It keeps best for about 2 to 3 months. Thaw it overnight in the refrigerator, or reheat it from frozen over low heat with a splash of water or broth, stirring as it loosens. Add fresh lemon juice or parsley after reheating if you want to revive their bright flavor.

Frequently Asked Questions

Do I need to soak lentils before making this soup?
No. Brown and green lentils cook in the soup without soaking. Pick through them for debris and rinse them before adding them to the pot. Soaking is optional, but it changes the cooking time, so check for tenderness earlier if you choose to soak them.

Can I use canned lentils?
Yes, but they are already cooked, so do not simmer them for the full 32 minutes. Cook the vegetables, spices, tomatoes, and broth as directed, then add about 3 cups (720 ml) drained and rinsed canned lentils for the final 10 minutes. Reduce the broth by about 1 cup (240 ml) to account for the shorter cooking time, and taste for salt.

Why are my lentils still hard?
Some dried lentils are older and take longer to soften, and acidic ingredients can slow softening when added early. This recipe includes tomatoes from the start, so give the lentils extra time at a gentle simmer if needed. Keep them covered with liquid, avoid a vigorous boil, and continue checking every 5 minutes until tender.

Can I make the soup vegetarian or vegan?
Yes. Use vegetable broth, which makes the recipe vegan as written, and choose plant-based toppings instead of dairy yogurt. If using chicken broth, the soup is not vegetarian, but the remaining ingredients stay the same.

Can I make it in a slow cooker?
For a slow-cooker version, sauté the onion, carrots, and celery in a pan first, then cook the garlic, tomato paste, and spices briefly before transferring everything to the cooker. Add the lentils, tomatoes, broth, bay leaf, salt, and pepper; cook on low for about 6 to 7 hours or high for about 3 to 4 hours, checking that the lentils are tender. Add spinach and lemon near the end. Slow cookers vary, so use tenderness as the guide and avoid leaving the soup on a long warm setting, where the lentils can become overly soft.

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