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    A Full Living » Blog » Soups and Stews

    Published: Sep 19, 2022 by Briana · This post may contain affiliate links.

    Keto Tomato Soup

    Jump to Recipe Print Recipe
    keto tomato soup

    This Low Carb Tomato Soup Recipe is made with roasted fresh tomatoes and fresh basil. It's creamy, decadent, and wholesome. Great for easy lunches or a side for dinner. It's made in a few simple steps with a handful of ingredients!

    close up shot of keto tomato soup drizzled with heavy cream, olive oil, fresh pepper, parmesan, and basil.

    There's really nothing quite like homemade tomato soup. This recipe makes a very large batch of flavorful soup, and we love making it year-round, especially near the summer's end. It's a great way to use ripe, end-of-season tomatoes!

    This recipe is perfect for reheating throughout the week. It can easily be halved for a smaller batch as well. Only 5 grams of net carbs per serving, making it ideal for the keto diet!

    Looking for more delicious low carb soup recipes? Try this keto cabbage soup, this loaded keto 'potato' soup, or this keto butternut squash soup!

    Jump to:
    • ❤️Why we love this recipe
    • 🍅Ingredients
    • ✏️Ingredient notes
    • 📖Instructions
    • ✨Tips & tricks
    • ✏️Substitutions & variations
    • 💭Frequently asked questions
    • ⏲Equipment
    • 🥣Storage
    • ♨️Reheating
    • 🌟Leave a review!
    • 📖 Recipe

    ❤️Why we love this recipe

    • Simple ingredients - This simple soup is made with just a handful of ingredients that can be found at any local grocery store.
    • Bursting with tomato flavor - Roasted tomatoes and fresh basil bring loads of flavor to your taste buds.
    • One of our favorite comfort foods - What's not to love about hot soup when the cold weather starts to roll in? This delicious soup is one of our favorites, especially at the time of year when it begins to transition from summer to fall.
    • Great for meal prep - We make a large batch of this soup every time we make it, so that's it's good to reheat throughout the week. You can scale this recipe up or back as needed as well.

    🍅Ingredients

    Here are the main ingredients you'll need for this tomato basil soup. You can find full ingredient quantities and nutritional information in the recipe card.

    ingredients to make keto tomato soup laid out with text overlaying the ingredients to denote each ingredient.

    ✏️Ingredient notes

    • Onion - Yellow onion, cut into large chunks. These will be roasted in the oven alongside the tomatoes.
    • Fresh tomatoes - Use a ripe, plum variety like Roma tomatoes. You can also use cherry tomatoes for a sweeter soup, but this will increase the carb count. Use high-quality canned tomatoes, like San Marzano tomatoes if tomatoes are out-of-season and flavorless.
    • Olive oil & unsalted butter - We use both for the best flavor. Butter adds a luscious creaminess that we really enjoy, but you can also just use one or the other.
    • Chicken broth - We used chicken bone broth for more protein and nutrients. Chicken stock or vegetable stock can be used for vegetarian diets.
    • Kosher salt & black pepper
    • Garlic cloves - Minced.
    • Italian seasoning
    • Fresh basil - Optional.
    • Heavy whipping cream & parmesan cheese - Optional, if you prefer a creamy tomato soup like us. You can also serve it with a dollop of sour cream.

    ** If the soup needs a hint of sweetness to balance the acidity, feel free to sweeten it to taste with your favorite keto-friendly sweetener. We love Swerve. We didn't end up using any, as our tomatoes were quite sweet and in season.

    📖Instructions

    📋Prep work

    • Wash, core, and quarter the tomatoes.
    • Quarter the onions.
    • Mince garlic.
    • Grate parmesan cheese.
    • Preheat the oven to 425°F.

    Step 1 - Roast tomatoes and onions

    *If using canned tomatoes, skip to step 2.

    Add tomatoes and onions to a large baking sheet. Toss with some olive oil, salt, and pepper.

    tomatoes and onions on a baking sheet with a wooden spoon.

    Roast until softened and beginning to wrinkle and char, about 30 minutes, tossing halfway through.

    roasted tomatoes and onions on a baking sheet.

    Step 2 - Cook garlic

    Meanwhile on the stovetop, in a stock pot or dutch oven, melt butter over medium heat. Add the garlic cloves and stir constantly, to ensure the garlic doesn't burn, and cook for 30 seconds to 1-minute, until garlic is fragrant.

    *If using canned tomatoes, cook onion with the garlic until softened and translucent, about 5-7 minutes, then add in canned tomatoes and follow the rest of the instructions.

    garlic cooking in a dutch oven with butter, and wooden spoon in the pot.

    Step 3 - Add back tomatoes, onions, and liquids

    Add the cooked tomatoes and onions to the garlic right away once fragrant to cool the garlic down, then pour in the broth. Season with salt, pepper, and Italian seasoning.

    Bring to a boil, then reduce to a simmer and cover. Simmer for 10 minutes.

    cooked tomatoes and onions in a soup pot with italian seasoning and broth.

    Step 4 - Add basil

    If using, add basil and stir to wilt.

    fresh basil in a stockpot of soup with tomatoes.
    tomato soup in a dutch oven with onions, and wilted basil.

    Step 5 - Blend

    Using an immersion blender or regular blender, blend the soup until smooth.

    hand holding an immersion blender and pureeing tomato soup in a pot.

    Step 6 - Add cream (optional)

    Reduce heat to a simmer, and if using, add heavy cream to warm through.

    hand pouring heavy cream into a dutch oven full of tomato basil soup.

    Step 7 - Add parmesan cheese (optional)

    If desired, add parmesan cheese in small batches, stirring completely before adding more cheese.

    parmesan cheese in a pot of tomato soup with cream.

    Step 8 - Add final touches

    Adjust seasonings to taste, then add to bowls. Garnish with cream, olive oil, salt, pepper, fresh basil, and parmesan to taste. Enjoy!

    two bowls of keto tomato soup topped with cream, fresh basil, and olive oil.

    ✨Tips & tricks

    • Use the best tasting ingredients you can! Since this recipe has so few ingredients, use the best ones you can find. Whenever possible, use fresh, ripe, in-season tomatoes. With that being said, if tomatoes are out of season, opt for high-quality canned tomatoes instead.
    • If adding parmesan, grate it fresh & add to soup slowly. Parmesan is optional, but if using, be sure to add it fresh and slowly in batches, and melt it completely before adding more. Pre-shredded cheese tends to have anti-caking agents and other additives that make it harder to melt smoothly, so grate it fresh if possible.
    • Don't boil once the cream is added! Be careful of heating too quickly once cream is adding to the soup (if using). Gently simmer once cream is added to the broth or when reheating later. Heating too much will cause the cream to curdle.
    • Don't burn the garlic. Once the tomatoes and onions are roasted, this soup comes together very quickly. You will need to stir the garlic constantly to ensure it doesn't burn. If it burns, you need to start over.
    • For a thicker soup, start with only 1 cup of broth. If you prefer a really rich and thick soup, feel free to reduce the amount of liquid added, and add more as needed to thin.
    • Strain soup for an extra creamy mouthfeel. This is more of a personal preference. Tomato seeds in the soup can add a bit of slightly bitter flavor, as well as create a texture that some may not enjoy as much. If you like, use a metal sieve to strain out any seeds or chunks in the soup.
    • Salt slowly at all stages of cooking, and to taste. Make sure to add salt during every new step of the cooking process for the best flavor. Taste as you go, and add salt as needed. You may need to add more or less depending on your tastebuds, as well as if you use parmesan cheese in the soup.
    bowls of creamy tomato soup with cream, olive oil, basil, parmesan, and garlic surrounding it.

    ✏️Substitutions & variations

    The ingredients are pretty straightforward, but here are a few simple swaps you can make.

    • Dairy-free option - Feel free to use all olive oil in place of butter, as well as omit the heavy cream and parmesan cheese. If you're still hoping for a creamy soup, use coconut cream or full-fat coconut milk in place of heavy cream.
    • Paleo - Use coconut cream, omit the butter, and parmesan cheese.
    • Vegan - Follow all steps above to make this soup dairy-free, and also be sure to use vegetable broth or stock instead of chicken broth.
    • Add red peppers - Adding a few red bell peppers to the mix can help deepen and enhance the flavor a lot.
    • Deeper tomato flavor - Add a bit of tomato paste when sauteeing the garlic for a richer, slightly sweeter tomato flavor in the soup.
    • Spicy - Add a hint of spice by adding red pepper flakes to the soup.
    • Roasted garlic - You can also roast the garlic cloves alongside the tomatoes and onions for a sweeter flavor.
    • Thicker soup - Want a thicker, more hearty bowl of soup? Try adding some cream cheese, or xanthan gum to the soup to thicken it according to your preference.

    💭Frequently asked questions

    What makes this soup keto-friendly?


    Homemade tomato soup has just a handful of ingredients, but store bought versions like Campbell's tomato soup have around 20 net carbs per serving because they are packed with added sugar.

    Make it healthier and tastier, and only 5 net carbs per serving, by using straight forward, wholesome ingredients and no added sugar.

    ⏲Equipment

    Luckily, this recipe is pretty standard and you really don't need much to make it.

    • Baking sheets for roasting.
    • A set of sharp knives for cutting vegetables. We like this self-sharpening knife set!
    • We love our enameled cast iron dutch oven, as it's super easy to clean. You can use any dutch oven or stock pot.
    • If using enameled cast iron, make sure to use silicone or wooden utensils, so you don't scrape the bottom of the pan.
    • You will need an immersion blender (we love this cordless one!) or a powerful high speed blender.
    • We use a Microplane to finely grate the parmesan cheese.

    🛒Shop this recipe

    Need supplies for this recipe? We've linked our favorites right here in our Amazon Store! You don't pay anything extra if you shop using our link, but we get a small percentage of the sale. 

    A Full Living is a participant in the Amazon Services LLC Associate program, an affiliate advertising program designed to promote a means for sites to earn advertising fees by linking products to amazon.com. We only share products we use and love.

    bowl of creamy tomato soup with fresh cream, olive oil and and basil.

    🥣Storage

    This soup saves really well. Store in an airtight container in the fridge for up to 5 days. To freeze, we'd recommend not adding parmesan or cream until time to serve. Allow soup to cool to room temperature before transferring it to a freezer-safe container. Freeze for up to 6 months.

    ♨️Reheating

    To reheat on the stovetop, add to a stock pot or dutch oven and simmer gently until warmed through.

    In the microwave, microwave in 15-20 second intervals until hot.

    🌟Leave a review!

    Make sure to leave a 5-star review below! This helps other readers find our recipes via Google, and encourages them to try them. Also be sure to leave a comment with your experience!

    Take a photo and share with us by tagging us on Instagram or follow along on Pinterest for more ideas!

    📖 Recipe

    keto tomato soup

    Keto Tomato Soup

    This Keto Tomato Soup is simple to make, super creamy, and is made with fresh roasted tomatoes, basil, and parmesan cheese. You only need a few ingredients to make this perfect soup!
    5 from 1 vote
    Print Pin Rate SaveSaved!
    Prep Time: 10 minutes
    Cook Time: 45 minutes
    Total Time: 55 minutes
    Servings: 16 servings
    Author: Briana

    Ingredients

    • 4 pounds tomatoes, quartered (Roma, plum, beefsteak, or cherry. Can be substituted for canned tomatoes, see notes)
    • 2 medium yellow onions, quartered
    • 2 tablespoons olive oil
    • 4 teaspoons kosher salt, divided (to taste)
    • 4 tablespoons unsalted butter
    • 8 cloves garlic, minced
    • 2 teaspoons Italian seasoning
    • 4 cups chicken broth
    • handful of fresh basil (optional)
    • 8 ounces heavy cream
    • freshly grated parmesan cheese to taste
    • olive oil, heavy cream, salt, pepper, parmesan & basil to garnish

    Instructions

    • Preheat the oven to 425°F. Add tomatoes and onions to a baking sheet. Toss with olive oil, salt, and pepper. Roast for 30 minutes, until the tomatoes begin to wrinkle and char. (If using canned tomatoes, skip to step 2).
    • In a stockpot over medium heat, melt butter. Add garlic cloves, and move around frequently to cook garlic until fragrant, about 1 minute. (If using canned tomatoes, add onions alongside the garlic with a big pinch of salt, and cook until onions are softened and translucent about 5 minutes.)
    • Once the garlic is fragrant, immediately add the tomatoes and onions to cool off the garlic to prevent it from burning. Add in broth or stock, along with salt, pepper, and Italian seasoning. Bring mixture to a boil, then reduce to a simmer and cover. Allow mixture to simmer for 10 minutes.
    • Add in optional basil, and stir to wilt. Using a blender or an immersion blender, blend the mixture until smooth.
    • Reduce heat to low, then stir in heavy cream if using to warm through. Slowly add in freshly grated parmesan cheese in batches, and stir to melt completely before adding more cheese.
    • Adjust seasonings to taste, then serve with heavy cream, olive oil, salt, pepper, basil, and parmesan. Enjoy!
    • Store leftovers in an airtight container in the fridge for up to 5 days.

    Notes

    • To substitute for canned tomatoes, simply skip the tomato roasting step, and saute onions and garlic together before adding canned tomatoes (with liquid) to the stock pot. Continue on with the remaining steps. 
    • Be careful not to heat soup with cream or cheese too quickly, as it can curdle the dairy or cause cheese to clump together. 

    Nutrition

    Calories: 121kcal | Carbohydrates: 7g | Protein: 2g | Fat: 10g | Saturated Fat: 5g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 0.1g | Cholesterol: 25mg | Sodium: 810mg | Potassium: 323mg | Fiber: 2g | Sugar: 4g | Vitamin A: 1246IU | Vitamin C: 17mg | Calcium: 34mg | Iron: 1mg

    These nutrition facts are provided as a courtesy and are only estimates. We cannot guarantee the accuracy.

    Did you love it?If you made this recipe, make sure to show us on Instagram at @AFullLiving or tag #AFullLiving! We love to see what you guys are making!
    Course: Soup
    Cuisine: American
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