This post may contain affiliate links. See our disclosure policy.

Lentil soup is the cheapest real dinner I know how to make, and this one pot version tastes like it took a lot more than a bag of lentils and a few vegetables. Onion, carrot, and celery cook down slowly, warm spices go in to bloom, and then everything simmers until the lentils are soft enough to mash against the side of the pot.

The step that separates good lentil soup from sad lentil soup is blending part of it. Pull about two cups out at the end, buzz it smooth, and stir it back in. The starch from those blended lentils thickens the whole pot into something with body, so you get a spoonful that holds together instead of brown broth with things floating in it.

And the lemon at the end is not optional. Lentils are earthy and a little flat on their own, and two tablespoons of lemon juice stirred in off the heat wakes the entire pot up. Add it last, though. Fresh lemon fades once it sits in a simmering pot, so a squeeze off the heat tastes brighter than the same two tablespoons stirred in at the start.

Why You’ll Love This Lentil Soup Recipe

Under two dollars a bowl. A bag of dried lentils, a few vegetables, and a carton of broth feed six people with change left over.
One pot, start to finish. Everything happens in the same Dutch oven, including the blending if you own an immersion blender.
Thick enough to eat with a fork. Blending two cups and stirring them back in gives the soup real body without any cream or flour.
It gets better on day two. The spices settle in overnight and the lentils keep absorbing broth, so leftovers taste more seasoned than the first bowl did.

Lentil Soup Ingredients

Use brown or green lentils, not red. Brown and green hold their shape through a 30-minute simmer, which is what gives this soup its texture. Red lentils dissolve completely and turn the pot into a smooth puree, which is a fine soup but a different one.

2 tbsp olive oil
1 large yellow onion, diced
2 carrots, peeled and diced
2 celery ribs, diced
4 cloves garlic, minced
2 tsp ground cumin
1 tsp ground coriander
1 tsp smoked paprika
1/2 tsp dried thyme
2 tbsp tomato paste
1 (14.5 oz) can diced tomatoes
1 1/2 cups brown or green lentils, rinsed and picked over
6 cups vegetable or chicken broth
2 bay leaves
1 tsp salt
1/2 tsp black pepper
3 cups chopped kale, tough stems removed
2 tbsp lemon juice
1/4 cup fresh parsley, chopped, for serving

Recipe Variations

Brown 1 pound of ground turkey in the pot before the vegetables go in and leave it there for a meatier soup. Cook it to 165°F first, since turkey is poultry and needs a higher safe temperature than beef does.
Use red lentils instead of brown or green. They fall apart in about 20 minutes, so cut the simmer short and skip the blending step entirely, since they’ll thicken the pot on their own.
Swap the kale for baby spinach. Stir in 4 cups at the very end and it wilts down in about a minute, no extra simmering needed.

How to Make Lentil Soup

Build the base: Heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion, carrots, and celery and cook for 8 to 10 minutes, stirring now and then, until the vegetables are soft and the onion turns golden at the edges. Don’t rush this part, it’s where the sweetness in the finished bowl comes from.
Bloom the spices: Stir in the garlic, cumin, coriander, smoked paprika, and thyme and cook for 1 minute, until everything smells toasty. Add the tomato paste and cook 1 minute more, stirring, until it darkens from bright red to brick.
Add the lentils and broth: Pour in the diced tomatoes, lentils, broth, bay leaves, salt, and pepper. Scrape the bottom of the pot to lift the browned bits, then bring it to a boil.
Simmer: Reduce the heat to low, cover partially, and simmer for 30 to 35 minutes, until the lentils are tender enough to mash easily against the side of the pot but still hold their shape. Stir once or twice so nothing sticks.
Thicken it: Fish out the bay leaves. Blend about 2 cups of the soup with an immersion blender right in the pot, or scoop 2 cups into a blender, puree until smooth, and stir it back in.
Wilt the kale: Stir in the chopped kale and simmer uncovered for 5 minutes, until it’s tender and deep green. Add a splash of water or broth if the pot has gotten thicker than you like.
Finish with lemon: Take the pot off the heat and stir in the lemon juice. Taste and add more salt if it needs it, which it usually does. Ladle into bowls and scatter parsley over the top.

Recipe FAQs

Do I Need to Soak Lentils Before Making Lentil Soup?

No. Unlike dried beans, lentils cook through in about half an hour straight from the bag. Just rinse them in a strainer and look them over for the occasional small stone or shriveled one.

What Kind of Lentils Are Best for Lentil Soup?

Brown or green. They soften without falling apart, so you get distinct lentils in every spoonful. Red and yellow lentils break down into a puree, and French green lentils stay firmer than most people want in a soup.

Why Is My Lentil Soup Thin and Watery?

Either it didn’t get blended or it needs more time uncovered. Puree 2 cups and stir them back in, and if it’s still loose, simmer it uncovered for another 10 minutes to cook some liquid off.

Can I Make Lentil Soup in a Slow Cooker?

Yes. Cook the vegetables and spices on the stove first, then move everything except the kale and lemon to the slow cooker with the broth. Cook on low for 6 to 7 hours or high for 3 to 4, then stir in the kale and lemon at the end.

How Do I Keep Lentil Soup Vegetarian?

Use vegetable broth instead of chicken broth and everything else stays the same. A teaspoon of soy sauce or a parmesan rind dropped in during the simmer adds back some of the savory depth chicken broth brings.

Cooking Tips

Hold the lemon juice until the pot is off the heat. Fresh lemon fades fast in a simmering pot, so the same two tablespoons taste much brighter stirred in at the end. Taste once it’s in and add another splash if you want more.
Give the lentils a swirl in a bowl of water before they go in the pot. Dust and any shriveled, hollow ones float up, so skim those off the surface. Grit and the rare little pebble settle to the bottom, so pour the lentils out and leave that last bit of water behind.
Season in two passes, once when the broth goes in and again at the very end. Lentils soak up salt as they cook, so a pot that tasted right at minute five will taste flat at minute thirty-five.

Storage and Freezing

To store: Refrigerate in an airtight container for up to 4 days. It thickens a lot overnight, so thin it with broth or water when you reheat.

To freeze: Lentil soup freezes very well for up to 3 months. Cool it completely, leave an inch of headroom in the container, and thaw overnight in the fridge. The kale softens but the lentils hold up fine.

To reheat: Warm it on the stove over medium with a splash of broth, stirring, until it’s steaming and reaches 165°F. The microwave works too, in 1-minute bursts with a stir between each.

How to Serve Lentil Soup

Lentil soup wants bread more than anything else, so a torn hunk of crusty sourdough or warm pita does the job. A grilled cheese on the side turns it into a full dinner for kids who are suspicious of soup. If you want something green next to it, a simple arugula salad with lemon and olive oil echoes the lemon in the pot.

Loved This Recipe?

Lentil soup costs a few dollars, takes about an hour, and reheats better than almost anything else in the fridge.

Leave a star rating in the comments below, it helps other people find this recipe. Made it? Tag @allwellfed on Instagram, I love seeing this one in other people’s kitchens.

Equipment

Dutch Oven

Ingredients

2 tbsp olive oil
1 large yellow onion diced
2 carrots peeled and diced
2 ribs celery diced
4 cloves garlic minced
2 tsp ground cumin
1 tsp ground coriander
1 tsp smoked paprika
1/2 tsp dried thyme
2 tbsp tomato paste
1 (14.5 oz) can diced tomatoes
1 1/2 cups brown or green lentils rinsed and picked over
6 cups vegetable or chicken broth
2 bay leaves
1 tsp salt
1/2 tsp black pepper
3 cups chopped kale tough stems removed
2 tbsp lemon juice
1/4 cup fresh parsley chopped, for serving

Get Recipe Ingredients

Instructions

Build the base: Heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion, carrots, and celery and cook for 8 to 10 minutes, stirring now and then, until the vegetables are soft and the onion turns golden at the edges. Don’t rush this part, it’s where the sweetness in the finished bowl comes from.
Bloom the spices: Stir in the garlic, cumin, coriander, smoked paprika, and thyme and cook for 1 minute, until everything smells toasty. Add the tomato paste and cook 1 minute more, stirring, until it darkens from bright red to brick.
Add the lentils and broth: Pour in the diced tomatoes, lentils, broth, bay leaves, salt, and pepper. Scrape the bottom of the pot to lift the browned bits, then bring it to a boil.
Simmer: Reduce the heat to low, cover partially, and simmer for 30 to 35 minutes, until the lentils are tender enough to mash easily against the side of the pot but still hold their shape. Stir once or twice so nothing sticks.
Thicken it: Fish out the bay leaves. Blend about 2 cups of the soup with an immersion blender right in the pot, or scoop 2 cups into a blender, puree until smooth, and stir it back in.
Wilt the kale: Stir in the chopped kale and simmer uncovered for 5 minutes, until it’s tender and deep green. Add a splash of water or broth if the pot has gotten thicker than you like.
Finish with lemon: Take the pot off the heat and stir in the lemon juice. Taste and add more salt if it needs it, which it usually does. Ladle into bowls and scatter parsley over the top.

Notes

Blend about 2 cups of the finished soup and stir it back in; that starch is what thickens the pot without any cream or flour. Stir the lemon juice in off the heat, since fresh lemon fades in a simmering pot and tastes brightest added at the end. Store leftovers 3-4 days in the fridge and reheat until steaming, to an internal temperature of 165°F.

If you made this, leave a star rating down in the comments. It takes about ten seconds, and it’s how other cooks decide whether a recipe is worth trying.