This Slow Cooker Tomato Soup is a simple yet delicious recipe that is perfect for a comforting and nostalgic meal. It cooks all day in the crockpot (filling your home with the most amazing aroma), resulting in a creamy, robust, and well-rounded tomato soup everyone in the family will love.
Have you ever tried Marcella Hazan's famous sauce? I first learned of that simple, yet profound butter and onion tomato sauce about a decade ago, and it is now the only way I make tomato sauce. Over the years I've tweaked it to fit my own preferences, adding a bit more spices and herbs, as well as a pinch of sugar. I also started cooking it in the slow cooker all day. My family loves that tomato sauce so much that I started using that basic technique of cooking the tomatoes with a whole onion and butter to make tomato soup too.
Thus, this Slow-Cooker Tomato Soup came to be. It's well-balanced, super flavorful, and incredibly creamy. Plus, it's made simply in the slow cooker with little hands-on cooking time. It is my kids' favorite soup recipe (served alongside grilled cheese, of course), and I hope it becomes a favorite in your home, too.
So, let's get to making it! You can jump around the article using the menu below, or you can just head right to the bottom for the complete recipe.
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Ingredients Needed
Here is a brief overview of the ingredients needed for this recipe. The full recipe with quantities is listed below this text in the recipe card. If substitutions are available for this recipe, they'll be listed here. If you don't see a substitution you are looking for, please leave a comment below.
- whole peeled San Marzano tomatoes + crushed San Marzano tomatoes (see note)
- onion
- butter
- sugar
- kosher salt
- garlic powder
- dried oregano
- chicken or veggie broth (use chicken unless you need this to be a vegetarian soup)
- heavy cream
Why San Marzano Tomatoes?
This recipe calls for two different types of canned tomatoes, with both of them being San Marzano tomatoes. This is simply because they lend the best flavor for this recipe as far as canned tomatoes are concerned. This recipe is so easy, except for this small instruction of calling for a very specific type of tomato. They are worth the effort to seek out and buy for this recipe.
Can you make this recipe without canned San Marzano? Sure, it just won't be as good.
The one exception to this is if you are using homegrown or farm heirloom tomatoes. And you certainly can use those for this recipe, just be sure to remove the skin and stem from them before using them in this recipe.
How to Make It
Not only is using the slow cooker a good choice for making dinner (for all the obvious reasons) but it also is key to the deep flavor of this tomato soup recipe. The low and slow simmer of the tomato sauce with the butter and onion really helps to soften the acidity just enough, while enhancing the tomato flavor. It's a truly smooth and enjoyable tomato soup.
This is a quick visual overview mixing together the dough. If you are looking for the full recipe, keep scrolling!
Step 1: Add all ingredients, except for the heavy cream, to a large slow cooker and cook all day.
Step 2: Once done, remove the onion and blend until smooth.
Step 3: Add in the heavy cream.
Step 4: Taste and adjust seasoning.
Freezing Leftover Tomato Soup
This tomato soup freezes really well. It's best if it's frozen without the addition of heavy cream. So, if you are making it with plans to freeze it for later use, store it in an airtight container without the cream for up to 3 months. When ready to serve, defrost overnight, then reheat the soup on the stovetop and add the cream according to the instructions.
However, I have successfully frozen it with the heavy cream, though it does need to run it through the blender after it defrosts.
More Tomato-Based Recipes
More Soup Recipes
Making this Slow Cooker Tomato Soup? Be sure to leave a comment with a star ⭐️⭐️⭐️⭐️⭐️ review on your experience! Have a question? Leave a comment below and I’ll get back to you as quickly as I can!
PrintFull Recipe
Slow Cooker Tomato Soup
- Prep Time: 00:05
- Cook Time: 06:00
- Total Time: 6 hours 5 minutes
- Yield: Serves 6
- Category: Soup
- Method: Slow Cooker
Description
A creamy and nostalgic childhood favorite, this Slow Cooker Tomato Soup cooks gently all day, filling your home with the most amazing scent that makes your family eager for dinner time. This creamy tomato soup is made with just a few ingredients but has a well-rounded robust flavor.
Ingredients
For Tomato Soup:
- 1 (28-ounce) can whole peeled san marzano tomatoes
- 1 (28-ounce) can crushed san marzano tomatoes
- 1 onion, peeled, but left whole
- 4 tablespoons unsalted butter
- 2 tablespoon sugar
- 2 teaspoons coarse kosher salt, more as needed (see note)
- 2 teaspoons garlic powder
- 2 teaspoons dried oregano
- 1 cup chicken or veggie broth, or more if needed
- ¼ cup heavy cream
For Serving:
- Fresh basil
- Parmesan cheese
Instructions
- Add all ingredients, except for the heavy cream, to a large slow cooker and cook on high for 4-6 hours or low for 6-8 hours.
- Once done, remove the onion and discard.
- Using an immersion blender, blend the soup until smooth.
- Stir in the heavy cream. Taste and adjust the seasoning, adding more salt when necessary.
- Serve with fresh basil and parmesan cheese, if desired.
Notes
This recipe was tested using Diamond Crystal coarse kosher salt. If you use Morton's kosher salt or fine salt, decrease the volume by half.
Why specifically San Marzano tomatoes? Simply because they offer the best flavor for this simple tomato soup using canned tomatoes. Most grocery stores will sell canned San Marzano, so be sure to grab them if you can to use in this recipe.
This recipe was inspired by Marcella Hazan. Recipe originally published in 2022, but updated with fresh photos in 2024.
Laura
This is my go-to tomato soup recipe !!!! I decided to add a personal twist by including a bay leaf, a red bell pepper, two carrots, and a celery rib, and the result was absolutely sublime. . Your recipe is a true gem, and I'm so grateful to have stumbled upon it. Thank you for sharing your culinary genius with us!"