Slow Cooker Creamy Tomato Lentil Soup Recipe • 5★

Updated August 7, 2025

Rachel Vanni for The New York Times. Food Stylist: Simon Andrews.

A summer soup is not an oxymoron. Take this lively lentil soup, rich and aromatic from both fresh and cooked tomatoes, and basil. Adding fresh tomatoes and basil at both the beginning and end of cooking ensures you get both their mellow, sweet side as well as their fresh, zingy side. The tomato paste and cream lend their sturdy flavors in a way that’s reminiscent of vodka sauce, while the lentils almost melt away into the background. The slow cooker is actually a great warm-weather tool, because it doesn’t heat up your kitchen the way the oven does, and it uses very little energy. This soup holds very well on warm before you add the finishing ingredients, making the timing flexible and weeknight-friendly.

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1 pound 12 ounces tomatoes, roughly chopped, divided (see Tip)

1 ½ cups red lentils, rinsed

4 garlic cloves, smashed and chopped

1 large basil sprig plus 1 cup roughly chopped basil

¼ cup tomato paste

2 tablespoons olive oil

1 tablespoon kosher salt (such as Diamond Crystal)

1 ½ teaspoons sugar

1 teaspoon dried oregano

Juice of 1 lemon

¾ cup heavy cream

Step 1In 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.

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 2Remove 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.

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 3Stir 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.

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.

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!!!

My lentils never really cooked and I don’t know why. Did 4 hours on high, then another hour, then gave up and just ate them crunchy. My crockpot doesn’t usually have a problem, so???

Delicious. I doubled it on the stove (simmered 1.5 hours), added 1 tsp red pepper flakes, and used half Italian diced tomatoes and half tomatoes on the vine. I used coconut milk instead of cream as others recommended and it was still Italian-flavored without the stomach ache. Served it over arugula with good toast and a sprinkle of queso fresco on top. Will be making this one again.

The off-season version of this with canned tomatoes and dried basil is also delicious.

Source: https://cooking.nytimes.com/recipes/1027173-slow-cooker-creamy-tomato-lentil-soup