Slow Cooker Creamy Tomato Lentil Soup
Updated Aug. 8, 2025
- Total Time
- 4 hours 10 minutes
- Prep Time
- 10 minutes
- Cook Time
- 4 hours
- Rating
- Comments
- Read comments
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Ingredients
- 1pound 12 ounces tomatoes, roughly chopped, divided (see Tip)
- 1½cups red lentils, rinsed
- 4garlic cloves, smashed and chopped
- 1large basil sprig plus 1 cup roughly chopped basil
- ¼cup tomato paste
- 2tablespoons olive oil
- 1tablespoon kosher salt (such as Diamond Crystal)
- 1½teaspoons sugar
- 1teaspoon dried oregano
- Black pepper
- Juice of 1 lemon
- ¾cup heavy cream
Nutritional analysis per serving (6 servings)
357 calories; 16 grams fat; 8 grams saturated fat; 0 grams trans fat; 6 grams monounsaturated fat; 1 gram polyunsaturated fat; 42 grams carbohydrates; 8 grams dietary fiber; 8 grams sugars; 15 grams protein; 576 milligrams sodium
Note: The information shown is Edamam’s estimate based on available ingredients and preparation. It should not be considered a substitute for a professional nutritionist’s advice.
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Preparation
- Step 1
In a 6- to 8-quart slow cooker, combine 5 cups water, about 1 pound of the tomatoes (no need to be exact) along with any juices, the lentils, garlic, basil sprig, tomato paste, olive oil, salt, sugar, oregano and several generous grinds of black pepper. Cook on high for 4 hours.
- Step 2
Remove and discard the basil sprig. (It’s OK if it falls apart.) Whisk the soup vigorously to help the tomatoes and lentils fall apart and become smooth.
- Step 3
Stir in the remaining tomatoes and chopped basil, plus the lemon juice and the cream. Taste for seasoning and add more salt or pepper if necessary. The soup will thicken as it cools; add more water as necessary for the texture you like.
- Feel free to use any kind of tomato that you have on hand: Almost-falling apart beefsteaks would be lovely, as would cherry tomatoes or plum tomatoes. (If you use all cherry tomatoes, just be aware that there will be more tomato skin in the soup, so choose thinner skinned varieties, like Sungold, if you can.) Outside of tomato season, use a 15-ounce can of tomatoes to start, and finish with chopped cherry or grape tomatoes, which tend to be better than other varieties out of season.
Private Notes
Comments
I made this with Thai basil and coconut milk instead of cream. Really good.
Baking SODA. The idea is to provide a little bit of alkaline to neutralize the acid when mixing with the dairy. You don’t need a lot. Baking powder is slightly acidic. It will not do the same job.
@Olga - absolutely not! It's ready in about an hour on the stove (keep a lid on it to keep the heat in and encourage the lentils to cook all the way through!). For those who have had trouble with tomatoes and dairy "breaking" and getting grainy, add a healthy spoonful of baking powder to the pot! It will foam like crazy but stir well until the foam subsides and then add the dairy. Thanks to cookbook author Helen Myhre of the Norske Nook for that tip - game-changer!!! This soup is a favorite!!!
Temperature & Time Conversion Guide to substitute the oven for a slow cooker Low Setting: Aim for 225°F (107°C) for 8-9 hours, or about 160°C (325°F) for long cooking. High Setting: Try 250°F (120°C) for 4-5 hours, or around 325°F (160°C). General Time Rule: For every 8-12 hours on low, use 1-3 hours in the oven at 325°F (160°C). For every 4-6 hours on high, use 1.5-2.5 hours.
I accidentally put in split peas and then added the red lentils after and so it was double, and it actually worked out great! Big fiber, protein meal!
An Update: I have made this recipe at least six times over the past couple of months. It can be done on the stove in less than one hour. Instead of heavy cream, I used two tablespoons of sour cream which made the soup creamier. Also, I used two tablespoons of vinegar instead of lemon. Yesterday, I made this soup again and added a cup of frozen spinach at the end.