Slow Cooker Tomato Basil Soup
This post may contain affiliate links. Please see our privacy policy for details.
This slow cooker tomato soup is so cozy and so velvety creamy! A true set-and-forget dinner served with homemade parmesan cheddar croutons!

Featured Comment
Why you’ll love slow cooker tomato basil soup
- True set-and-forget dinner. There is absolutely no peeling, no pre-roasting required here. The slow cooker takes care of all that for you, breaking down the tomatoes and cooking low and slow for 7-8 hours. It’s just the best kind of hands-off cooking.
- Velvety, creamy goodness. Once the soup is cooked, you can easily use an immersion blender directly in the slow cooker to transform the chunky mix into a creamy, velvety, silky tomato soup in just minutes.
- The homemade croutons are everything. Sure, you can top off the soup with a swirl of heavy cream or half-and-half, but what really makes this is the crispy, crunchy, Parmesan cheddar croutons, soaking up all the flavor!
- Perfect to freeze for later. The leftover soup freezes very well (without the heavy cream), and can keep in the freezer for 3-4 months, offering ready-made cozy meals for months to come.
Key Ingredients
- Tomatoes: 2 large cans of whole peeled tomatoes or 3.5lb of fresh quartered tomatoes
- Liquids: tomato sauce and vegetable broth
- Aromatics: garlic, onion, bell pepper, and tomato paste
- Seasonings: oregano, sugar (to balance acidity), salt, and pepper
- Dairy: heavy cream or half-and-half
- Topping: homemade parmesan cheddar croutons (recipe below)
How to make slow cooker tomato basil soup
- Combine the ingredients. Add the canned tomatoes, tomato sauce, vegetable broth, garlic, onion, bell pepper, tomato paste, oregano, sugar, salt, pepper, and Parmesan rind into a 6-qt slow cooker, stirring until well combined. Then crush the whole peeled tomatoes into chunks using the back of a wooden spoon.
- Cook. Cover with a lid and cook on low heat for 7-8 hours or high heat for 3-4 hours until the tomatoes are very soft.
- Make the croutons. Spread the bread cubes in a single layer on a greased baking sheet and sprinkle with freshly grated cheddar cheese and Parmesan. Bake at 375°F for 10-12 minutes until crisp and golden, stirring halfway.
- Blend. Use an immersion blender directly in the slow cooker, blending until the soup is completely smooth, about 1-2 minutes.
- Finish. Slowly stir in the heavy cream and basil, seasoning one last time with salt and pepper. Pro tip: if you are planning for leftovers to freeze, hold off on the heavy cream.
- Serve. Ladle into bowls and top with croutons. Serve warm.

Tools For This Recipe
Slow Cooker Tomato Basil Soup: Frequently Asked Questions
Either works well! Canned tomatoes are generally more convenient as they are readily available year-round but fresh tomatoes are great when they are in season (May to October).
You can use a hand-held immersion blender directly in the slow cooker or you can transfer the soup to a blender, blending in batches until smooth.
Homemade cheddar croutons can keep for 2-3 days, stored in an airtight container (to maintain their crunch) in a cool, dry place. These have a short shelf life as the cheeses contain fat and moisture that can spoil faster than traditional croutons.
Store leftovers (with dairy) in an airtight container in the fridge for 2-3 days, gently reheating on the stovetop until warmed through.
Yes! Tomato soup freezes very well without the dairy, keeping in the freezer for 3-4 months.

Slow Cooker Tomato Basil Soup
Video
Ingredients
- 2 (28-ounce) cans whole peeled plum tomatoes with basil
- 1 (15-ounce) can tomato sauce
- 1 ½ cups vegetable broth
- 3 cloves garlic, minced
- 1 onion, diced
- 1 red bell pepper, diced
- 2 tablespoons tomato paste
- 1 ½ teaspoons dried oregano
- 1 teaspoon sugar
- Kosher salt and freshly ground black pepper, to taste
- 1 (3-inch) Parmesan rind, optional
- ⅓ cup heavy cream
- ⅓ cup chopped fresh basil leaves
For the parmesan cheddar croutons
- 4 cups ciabatta, baguette or sourdough bread cubes, stale and day-old
- 1 cup shredded extra-sharp cheddar cheese
- ¼ cup freshly grated Parmesan
Instructions
- Place tomatoes into a 6-qt slow cooker. Stir in tomato sauce, vegetable broth, garlic, onion, bell pepper, tomato paste, oregano, sugar, 1/2 teaspoon salt, 1/2 teaspoon pepper and Parmesan rind, if using, until well combined. Crush the tomatoes into chunks using the back of a spoon.
- Cover and cook on low heat for 7-8 hours or high heat for 3-4 hours.
- Puree with an immersion blender until desired consistency is reached. Stir in heavy cream and basil; season with salt and pepper, to taste.
- Serve immediately with parmesan cheddar croutons.
For the parmesan cheddar croutons
- Preheat oven to 375 degrees F. Lightly oil a baking sheet or coat with nonstick spray.
- Spread bread cubes in a single layer onto the prepared baking sheet; sprinkle with cheeses. Place into oven and bake until crisp and golden, about 10-12 minutes, stirring halfway; set aside and let cool.
Equipment
Notes
- Canned whole peeled tomatoes are best. Use canned whole peeled tomatoes such as San Marzano. They are packed at peak ripeness, offering maximum flavor and color. Avoid diced canned tomatoes as this can leave the soup with a grainy texture.
- Add a pinch of sugar. Tomatoes can be overly acidic. Add a small pinch of sugar (1 teaspoon) to mask the acidity and tartness without making the soup sweet.
- Save leftover Parmesan rinds. Get more out of those expensive Parmesan cheeses by using up the leftover rinds! Adding a Parmesan rind slightly thickens the broth and adds a level of nutty richness to the tomato soup.
- Vent the blender. An immersion blender will allow you to blend the soup directly in the slow cooker. But if you are using a standard countertop blender instead, remove the center cap of the lid to allow the steam to escape while blending, covering loosely with a towel to prevent splashes.
- Always add the dairy at the end. Dairy can curdle or separate during long hours of heat. Always stir in the heavy cream (or half-and-half) at the end of cooking time after blending the soup.
- Homemade croutons go a long way. Homemade croutons are so much easier to make than you think, allowing you to repurpose stale, leftover bread, and tasting so much better than store-bought croutons.
- Use a good quality sheet pan. A durable sheet pan is ideal when making the homemade croutons – it will last for years with minimal wear and tear, and will help achieve even cooking and avoid warping at high temperatures.
- Freeze without the dairy. Dairy-based soups tend to separate when thawed and reheated. Skip the heavy cream when freezing and allow the blended soup to cool completely, then portion into plastic freezer bags in individual servings. Label, date, and freeze for up to 4 months. To reheat, thaw overnight in the fridge and gently reheat over low heat, stirring occasionally, until warmed through.
Did you make this recipe?
Tag @damn_delicious on Instagram and hashtag it #damndelicious!
If i want to make the soup for 12 pers. Can i then just do that times 3? Or do i need to adjust some of the ingredients?
I wish that there was a list of nutritional facts do that I could make this. I want to make this but won’t because I am Diabetic. Is there anyway that you can list the nutritional facts of your recipes?
Highly recommend using an app like My Fitness Pal to enter in the exact ingredients you’re using and generate your nutritional facts from there. Even if she lists them for her recipe, it really could vary based on the specific brands you use.
So good! Cooked it exactly as written and tasted like a gourmet restaurant! This is definitely a keeper!
Great. I always leave out bell peppers as they do not like my wife. Everything was exact and perfect.
I followed the recipe exactly and it was awesome. I love tomato soup and this was a winner. Thanks.
This is so good! I have made it twice (both times with the croutons) for a crock pot cookoff and it’s always well received. I even won best vegetarian dish this year!
So easy to make and so good.
Made this Wednesday night … seriously the best homemade tomato soup recipe I’ve tried to date Makes the perfect amount too with leftovers to freeze Thank you ❤️
Made this morning as hurricane Milton heads toward our home before we loose power. Very easy recipe to follow. Simple ingredients. I had all the ingredients in my cupboard and fridge. Literally no stores open anyway.
We love that you enjoyed this recipe – it is a favorite of ours! We hope you and your family stay safe.
Amazing flavor. So easy!!! It cooks itself
Can I use coconut milk instead of heavy cream? or use 1/2 of both.
So easy and wonderful to come home to! Perfect for a busy weekday. We served this with grilled cheeses – delicious!
This was easy to put together and nice that my slow cooker took over for the most part! I took two days to make it, cooking through the 8 hours on first day and then adding additional ingedients on day two. I made this as directed with the exception of adding 1/2 cup finely grated parmesian reggiano directly into the soup. I did not make the croutons. It was delicious!
Thank you for posting this recipe. I forgot to buy a red pepper but the soup was amazing without it. I’ll try it with coconut milk next time.
This is wonderful! And personally I think tomato soup is better made with canned tomatoes.
Love, love, love your recipes. I have made many of them and they all turn out excellent. Look forward to making this soup, yummy!!
Okay soup, but probably not a repeat here. I had a small red bell pepper, but it still contributed a bit more to the flavor than I would have liked. The adults here ate it, but the kids didn’t like it at all. The croutons were appreciated by everyone. It’s hard to go wrong with bread and melted cheese.
SOUNDS YUMMY AND FULL OF COMFORT!!
Made it today and felt I was eating tomato sauce. I had substituted one can of tomatoes for crushed tomatoes with basil, that may have been my mistake. My husband thought it tasted very acidic. Any ideas on how to salvage the remaining soup?
Very tasty soup. A little bit too acid though.
You can use a very slight pinch of baking soda to tone down the acidity. But use only a tiny bit at a time until it suits your taste. Then you don’t have keep adding sugar or salt to balance the acidity. But, if you use too much baking soda it will make it VERY bland.