Creamy and loaded with bright, fresh flavors, this Easy Keto Tomato Basil Soup will quickly become a new family favorite – especially served with my Keto Cheesy Herb Muffins!!!

When I was a kid I used to love condensed tomato soup from a can, which my mom would usually serve alongside grilled cheese sandwiches made on cheap white bread with lots of butter. It was one of my favorite lunches and tasted even better when we’d just come inside from playing in the snow and were frozen to the bone. There was nothing better than having the day off from school for a snow day and trudging in and getting hit in the face with that sweet and pungent tomato soup smell at lunchtime.
Soup from a can isn’t something I’ve had in many years, but when I set out to create a tasty and easy keto tomato soup recipe, I started with the flavor and smell I remembered from my childhood in mind. Since my taste buds have gotten more discerning over the years, I wasn’t quite as enamored with the basic flavor of the tomato soup as is, so I threw in some dried basil and finished it with some pesto I had kicking around in the fridge at the end.
The addition of basil and pesto really took this already tasty keto tomato soup to the next level of “this is so good that I can’t stop eating it!”

Since we’re rounding the corner into Spring, this is a great transition soup that is still creamy and comforting, but also sports the brighter, fresher flavors that we’re all starting to crave about now. And you won’t have to stand over the stove for hours to make it, leaving you more time to enjoy the warmer (maybe) and sunnier (hopefully) days ahead.
The tasty looking muffins that you see in the photos are the Keto Cheesy Herb Muffins that I posted recently – and they are amazing. Tender and flavorful, they are the perfect accompaniment to this easy Keto Tomato Basil Soup and stand in perfectly as a keto replacement for the grilled cheese sandwiches of my childhood.

It’s my hope that this easy low carb tomato soup recipe will bring back pleasant childhood memories for you as it did for me, but even if it doesn’t, or if you haven’t been a fan of tomato soup in the past – I hope you’ll give it a try anyway and report back!
Easy Keto Tomato Basil Soup Recipe Note:
Be sure to use good quality canned tomatoes for this recipe since there aren’t a lot of other ingredients to mask the bitter or metallic flavor that you may get with low grade canned tomatoes. Homegrown, organic and/or San Marzano region tomatoes will typically give the best flavor. I use Cento brand (not getting paid for this, just really like Cento) when I can find them and I’m never disappointed – but any brand of tomatoes grown in and imported from Italy will likely yield delicious results.
That’s not to say this easy keto tomato basil soup won’t still be tasty made with U.S. tomatoes, just maybe not quite as good as it could be.
Easy Keto Tomato Basil Soup – Low Carb
- Total Time: 12 minutes
- Yield: 6 servings 1x
Description
A creamy and delicious low carb tomato soup recipe that takes just minutes to prepare! Keto, Atkins, and gluten free – this is an easy and tasty soup that you can feel great about serving to your family!
Ingredients
- 1 can (28 ounces) whole plum tomatoes (San Marzano preferred)
- 2 cups filtered water
- 1.5 teaspoons coarse kosher salt
- 1/2 teaspoon onion powder
- 1/4 teaspoon garlic powder
- 1 tablespoon butter
- 8 ounces mascarpone cheese
- 2 tablespoons granulated erythritol sweetener
- 1 teaspoon apple cider vinegar
- 1/4 teaspoon dried basil leaves
- 1/4 cup prepared basil pesto, plus more for garnish if desired
Instructions
- Combine the canned tomatoes, water, salt, onion powder and garlic powder in a medium saucepan.
- Bring to a boil over medium-high heat and then simmer for 2 minutes.
- Remove from the heat and puree with an immersion blender until smooth (or transfer to a traditional blender and blend, then return blended soup to the pan.)
- Return to the stove and add the butter and mascarpone cheese to the soup.
- Stir over low heat until melted and creamy – about 2 minutes.
- Remove from the heat and stir in the sweetener, apple cider vinegar, dried basil, and pesto.
- Serve warm.
- Store any leftovers in a covered container in the refrigerator for up to 5 days, or in the freezer for up to three months.
Notes
Net carbs per cup = 3 grams.
- Prep Time: 2 minutes
- Cook Time: 10 minutes
Nutrition
- Serving Size: 1 cup
- Calories: 258
- Fat: 23g
- Carbohydrates: 6g
- Fiber: 3g
- Protein: 4g
New to Keto and need help getting started?? Try following my 12 weeks of free keto menu plans, starting with the 3 Day Keto Kickstart and Keto FAQs!
Or if you’re already on keto but want to boost your results, try the wildly popular and effective IBIH 5 Day Keto Soup Diet and drop as much as 10 pounds!


l p says
forgot to rate it. thanks
l p says
this is exactly what I’m craving – going to try it soon. thanks
Carol says
Absolutely lovely! Didn’t need to add the sweetener but the vinegar was a brilliant touch! Thank you for posting.
MaryAnn says
I really want to try this, but could I leave out the sweetener and vinegar? How much would it affect the overall taste?
Kim Ferris says
Absolutely delicious! I omitted the sweetener, and I used whipped cream cheese, but next time I’m going to use the solid from coconut milk to make it squeaky. Thank goodness I have leftovers for lunch!
Lori says
Hello! I’m really excited to try this recipe! I found organic San Marzano tomatoes at my local store but they are fire roasted. Is that okay or should I look for regular ones? I don’t want to mess up the flavor if they shouldn’t be fire roasted. Thank you!
Mellissa Sevigny says
I didn’t use fire roasted so the flavor might be a bit different, but probably in a good way!
Jill L says
This recipe was so very delicious. I made it exactly except I substituted cream cheese for mascarpone because that’s what I had on hand. It waz amazing! Thank you so much
Jill Lawson says
Wanted to add this: I made this recipe again, this time using mascarpone cheese. I MUCH prefer the cream cheese vs mascarpone. I realize cream cheese adds a few more carbs but it also makes a richer, creamier more flavorful soup. The recipe as is is tasty as well but I highly recommend new makers to use cream cheese. It takes a little more manipulation to entirely melt (mascarpone melts much faster) but it’s worth it, imo.
Mellissa Sevigny says
Thanks for weighing in Jill!
PA says
I made it per the recipe and it’s delicious!
Thank you for upgrading my favorite soup to keto-worthy!
Chelsie says
Keto or not, this is the recipe I recommend to everyone for tomato soup. It does not get better than this!
Mellissa Sevigny says
Thanks so much! 😘
Chelle Simms says
My mother-in-law is diabetic, so she is very careful with her carbs. I’m Keto, so I’m rabid about my carbs. We had a conversation recently about tomato sou and grilled cheese sandwiches. We are having dinner with her tonight so I decided I would do this. First of all, this soup is beyond amazing. It is flavorful, rich and so easy to make. I used Healthy Life white bread for her sandwich (12 net carbs) while I used 1/2 of a Joseph’s Pita bread (7 net carbs). Even my carb eating husband loved it. Thank you so much for such an amazing and easy recipe for one of my favorite comfort foods. Seriously delicious – I’ll be making this a lot this winter!!
Mary says
This was excellent and will become a regular in our household!
Cherie Caldwell says
Made this soup last night. It was delicious.