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Hearty Lentil & Vegetable Soup

A cozy one-pot lentil soup with carrots, celery, tomato, and spinach, high in fiber and plant protein, naturally low in sodium, and gentle on digestion.

By Camille McLaughlin, RDN, LD, registered dietitian nutritionist

Built forVeganLunch
Also fits Balanced DASH GLP-1 Heart-Healthy High-Fiber Low-Carb Vegetarian
Carrots, celery, and onion go soft and sweet in the oil long before the broth arrives, and that is what the whole pot tastes of. Lentils hold their shape but turn creamy inside, cumin and thyme keep it from tasting plain, and spinach goes in at the end and wilts down in seconds.
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Why You'll Love This Recipe

A lentil soup with carrot, celery, and tomato that makes a big pot and improves for three days afterward, which is unusual enough to plan around. Cook it on a Sunday and Wednesday's bowl is the best one you get: the cumin and thyme spread out through the broth, the lentils soften and take up liquid, and the tomato loses the sharp edge it has straight from the can. It costs very little to make, it freezes in portions, and it quietly solves lunch for half a week.

Brown or green lentils are what you want here, and the difference matters more than the bins at the store suggest. Red and yellow lentils have had their skins taken off, so they collapse into the broth inside fifteen minutes, which is exactly right for a dal and wrong for a soup you want to find something in. Brown and green keep their skins, hold their shape through a long simmer, and are still intact after three days in the refrigerator.

Lentils bring fiber and plant protein in the same spoonful, which is why a bowl of this holds like a meal instead of leaving you hunting for something else an hour later. A slice of bread alongside or a spoonful of yogurt stirred through rounds it out further if you want that. Our Smoky Tempeh and Slaw Collard Wraps is another plant-based lunch built to travel.

A rustic bowl of hearty lentil and vegetable soup with carrots, celery and spinach in a tomato-tinged broth, steam rising, crusty bread beside it. Save
Prep: 15 minsCook: 30 minsTotal: 45 minsMakes: 6 servingsServing: about 1½ cups

Ingredients

Serves6Amounts change with the number. The nutrition panel is per serving, so it stays the same.
  • 3 cups cooked brown or green lentils (about 1 cup dry)
  • 2 medium carrots, diced
  • 2 celery stalks, diced
  • 1 small onion, diced
  • 3 cloves garlic, minced
  • 1 cup crushed tomatoes
  • 2 cups fresh spinach
  • 6 cups vegetable broth (choose a certified gluten-free, soy-free broth)
  • 2 tbsp olive oil
  • 1 tsp cumin
  • 1 tsp dried thyme
  • 1/2 tsp fine sea salt
  • black pepper

Instructions

  1. Take your time with the carrot, celery, and onion: Warm the olive oil in a heavy pot over medium heat and cook the diced onion, carrot, and celery for six or seven minutes, stirring now and again, until the onion is translucent and the carrot has given up its raw crunch. This is the base the entire soup stands on and it is the part not to rush, because vegetables that go into the broth still hard stay hard: a simmer in liquid softens them far more slowly than fat in a hot pan does. Add the garlic, cumin, and thyme for the last thirty seconds.
  2. Broth, tomato, and lentils, then twenty quiet minutes: Pour in the broth and the crushed tomatoes, add the cooked lentils, and bring it up to a gentle simmer rather than a boil. Twenty minutes is what it takes for the parts to stop tasting like separate things: the cumin moves out into the broth, the tomato loses its edge, and the lentils take up enough liquid to thicken the pot a little on their own. Stir every few minutes so nothing settles on the bottom and catches.
  3. Taste it before the spinach goes in: This is where you find out what the pot actually needs, and it is usually salt, acid, or a little more cumin. Add the salt a quarter teaspoon at a time and taste between each one, since broth brands vary enormously in what they already carry and a low-sodium box and a regular box are not the same starting point. If it tastes flat but is salty enough, a squeeze of lemon or a splash of vinegar does what more salt cannot.
  4. Spinach last, and only into what you are eating now: Stir the spinach in a handful at a time and let it wilt in the hot broth, which takes well under a minute, then season with the salt and pepper. If part of this pot is going into the freezer or into containers for the week, wilt spinach only into the portion you are serving tonight and add fresh leaves to the rest as you reheat them, because spinach that has been heated twice goes dark and loses any texture it had.
  5. Let it settle, then look at the thickness again: Leave the pot off the heat with the lid on for five minutes before you serve it. Lentils carry on drinking after the burner is off, so a soup that looked right at twenty minutes can be noticeably thicker by the time it reaches the bowl. Check it again then and loosen it with a little broth if it has gone further than you wanted. Those five minutes are also when the flavors stop being separate and sharp and start being one thing.
Nutrition Facts
6 servings per recipe
Serving sizeabout 1½ cups
Calories192
% Daily Value*
Total Fat 5g7%
Saturated Fat 1g4%
Trans Fat 0g
Cholesterol 0mg0%
Sodium 276mg12%
Total Carbohydrate 28g10%
Dietary Fiber 10g36%
Total Sugars 5g
Includes 0g Added Sugars 0%
Protein 10g
Vitamin D 0.0mcg0%
Calcium 61mg5%
Iron 4.2mg23%
Potassium 669mg14%
* Percent Daily Values are based on a 2,000 calorie diet. Values are computed from USDA FoodData Central and are estimates. Per serving (about 1½ cups).

Variations

  • Add more protein: the lentils cover most of it, but a cup of shredded chicken stirred in at the end, or a spoonful of yogurt on top, adds more. Either one takes the soup off vegan and vegetarian, though a plant-based yogurt keeps it plant-only.
  • Add more vegetables: chopped kale, diced potato, or extra carrot all simmer in without much fuss. Add the potato early enough that it actually cooks through.
  • Make it spicy: add a half teaspoon of red pepper flakes with the cumin so the heat blooms in the oil and runs through the whole pot.
  • Change the seasoning: swap the cumin and thyme for smoked paprika and a bay leaf for a Spanish turn, or for curry powder and a squeeze of lime for an Indian one.
  • Thicken it: blend a couple of cups of the finished soup and stir it back in, which gives you a creamy body without adding any cream.

Storage & Leftovers

Let it come down to room temperature before the lid goes on, ladled into a couple of shallow containers so it cools quickly, then refrigerate for four to five days. This one genuinely improves overnight and keeps improving for another two days after that: the cumin and thyme move out through the broth, the lentils soften and take up liquid, and the tomato settles into the background instead of sitting on top of everything else.

Reheat it on the stovetop over medium heat with a splash of broth, because lentils keep absorbing as they sit and the pot you put away as a soup comes back closer to a stew. Stir it up from the bottom, where the lentils settle into a dense layer. If it has thickened past what you want, loosen it with broth rather than water, so you are not diluting the seasoning at the same time as the texture.

It freezes for up to three months and is one of the better candidates for it, since nothing in the pot breaks down badly on thawing except the spinach. Leave that out of whatever is headed for the freezer and stir fresh leaves in when you reheat. Freeze it in single portions rather than one block, cool it completely first, and move a container into the refrigerator the night before you want it.

Notes & Tips

A gentle simmer, rather than a hard boil, keeps everything tender and lets the flavors come together.
  • Simmer gently: lentils cook best at a gentle simmer. A hard boil can make them burst and turn mushy.
  • Add spinach at the end: stir spinach in during the last minute. It wilts almost instantly and keeps its color.
  • Make it ahead: this recipe is friendly to batch-cooking; double it and portion into containers for the days ahead.
  • Salt at the finish: the broth already carries salt and the soup reduces as it simmers, so hold your own salt until the end and taste first.
  • It thickens overnight: lentils keep drinking liquid in the refrigerator, so add a splash of broth or water when you reheat a bowl.
  • Flexible swap: no onion? You can leave it out, or swap in a little chopped celery or chives.

Nutrition & Mindful Eating

One pot and a slow simmer, and the carrots, celery, onion and garlic that started it turn a bowl of lentils into something deeply savory by the time the spinach goes in.
  • Lentils, the diced vegetables and the crushed tomatoes soften into one another over the simmer. The lentils thicken the pot, the vegetables sweeten it, and the tomato brings the acidity that keeps something this hearty tasting bright.
  • Lentils hold their shape just enough to stay recognizable while their edges break down and body the whole pot. They carry plant protein and folate, and the soluble part of their fiber dissolves right into the soup.
  • Carrots, celery and onion cooked slowly in olive oil are the base of the entire thing, and the carrots stay a little sweet and firm in the finished bowl. Their carotenoids come across better because there is fat in the pot alongside them.
  • Spinach goes in at the end and wilts in the residual heat, staying dark green rather than turning gray. It brings iron, folate and vitamins A and C into the final few minutes.
  • Crushed tomatoes give the soup its color and its lift, and the vitamin C they carry helps your body take up the plant iron from the lentils and the spinach sitting beside them.
  • As you eat, feel the steam on your face and notice how soft the lentils have gone against the bite still left in the carrots, and let a warm bowl be a reason to sit down properly.

Frequently Asked Questions

Are lentils good for you?

Very, they're high in fiber and plant protein, low in fat, and have a gentle effect on blood sugar, making them a staple of heart-healthy and DASH eating.

Is this soup low in sodium?

Made with low-sodium broth and light added salt, yes. That is what makes it a good fit for blood pressure and heart health.

Can I freeze it?

Absolutely, it freezes beautifully for up to 3 months. Thaw and reheat with a splash of broth or water.

How long does it keep?

Four to five days refrigerated, and it is at its best on day two or three rather than the day you make it. It freezes for up to three months as well. The one thing worth holding back is the spinach: leave it out of anything going into the freezer and stir fresh leaves in as you reheat.