Lentil soup is a Mediterranean-style pot of brown lentils, carrots, celery, tomatoes, and warm spices, and this slow cooker version cooks all day while you do something else. It sounds plain, I know, but the lentils break down into a thick, stew-like soup that is deeply savory and filling in a way few vegetarian dishes manage. What does the lemon do? The juice goes in at the end, and without it a soup that has cooked for hours tastes flat. The cumin, smoked paprika, and coriander give it a warm base, and the lemon brightens it right at the finish.
Stir in a couple handfuls of baby spinach right before serving. It wilts in seconds and adds color and a slight bitterness that rounds out the bowl. Lesson learned.It adds richness and a peppery bite that makes the whole thing feel more substantial. This soup freezes well, costs very little to make, and feeds a crowd, which makes it one of the most useful recipes to have in your back pocket.
Combine Ingredients in Slow Cooker
Combine the rinsed lentils, diced tomatoes, diced carrots, diced celery, diced onion, garlic, vegetable broth, cumin, paprika, coriander, turmeric, salt, pepper, and bay leaves in a 6-quart slow cooker. Stir to combine everything. Cover and cook on LOW for 7 to 8 hours or HIGH for 4 to 5 hours, until the lentils are completely tender and the soup has thickened.
Finish with Greens and Lemon
Remove the bay leaves. Stir in the baby spinach and lemon juice. The spinach will wilt in the hot soup within a couple of minutes. The lemon juice brightens the soup and cuts through the earthy lentils. Taste and adjust seasoning with more salt or lemon juice if needed. The soup should be thick and hearty, almost like a stew.
Serve with Olive Oil
Ladle the soup into bowls and drizzle with extra-virgin olive oil. The olive oil adds richness and a peppery note that makes the soup feel more substantial. Serve with crusty bread or naan on the side. This soup tastes even better the next day, so it is excellent for meal prep.
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Slow Cooker Lentil Soup with Spinach and Lemon
- Total Time: 435 minutes
- Yield: 6 servings
Description
Brown lentils simmer all day in the slow cooker with carrots, celery, tomatoes, and warm spices until they break down into a thick, stew-like vegetarian soup. Baby spinach and lemon juice go in at the end, with olive oil drizzled over each bowl.
Ingredients
- 2 cups brown or green lentils, rinsed and picked over
- 1 can (14.5 ounces) diced tomatoes
- 3 medium carrots, diced
- 3 stalks celery, diced
- 1 large yellow onion, diced
- 4 cloves garlic, minced
- 6 cups vegetable broth
- 2 teaspoons ground cumin
- 1 teaspoon smoked paprika
- 1 teaspoon ground coriander
- 1/2 teaspoon ground turmeric
- 2 teaspoons kosher salt
- 1/2 teaspoon freshly ground black pepper
- 2 bay leaves
- 2 cups baby spinach
- Juice of 1 lemon
- 3 tablespoons extra-virgin olive oil for drizzling
Instructions
- Combine the lentils, diced tomatoes, carrots, celery, onion, garlic, vegetable broth, cumin, paprika, coriander, turmeric, salt, pepper, and bay leaves in a 6-quart slow cooker. Stir to combine.
- Cover and cook on LOW for 7 to 8 hours or HIGH for 4 to 5 hours, until the lentils are completely tender.
- Remove the bay leaves. Stir in the baby spinach and lemon juice. The spinach will wilt in the hot soup within a couple of minutes.
- Taste and adjust seasoning. Ladle into bowls and drizzle with extra-virgin olive oil.
Notes
- Brown and green lentils hold their shape best in the slow cooker. Red lentils dissolve completely, which gives a smoother, more puréed soup.
- Add the lemon juice at the end, after the spinach. Long-cooked lentil soup tastes flat without acid.
- The soup thickens as it sits, so add a splash of broth or water when you reheat it.
- Prep Time: 15 minutes
- Cook Time: 420 minutes
- Category: Main Course
- Cuisine: Mediterranean
Nutrition
- Serving Size: 1 serving
- Calories: 340
- Sugar: 6
- Sodium: 760
- Fat: 8
- Carbohydrates: 48
- Fiber: 14
- Protein: 20
Frequently Asked Questions
Can I use red lentils instead of brown or green?
Red lentils cook faster and dissolve completely, creating a smoother, more pureed texture. If you use red lentils, reduce the cooking time to 4 to 5 hours on LOW.
Is this soup vegan?
Yes, as long as you use vegetable broth. Check the label to make sure the broth does not contain any animal products.
How do I store and reheat leftovers?
Store the soup in an airtight container in the fridge for up to 5 days or freeze for up to 3 months. The soup will thicken as it sits. Add a small pour of broth or water when reheating to thin it to your preferred consistency.
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