Homemade crock-pot tomato soup is incredibly easy and comforting. A simple topping of very thinly sliced leek and grated cheese—Gouda or Cheddar work especially well—melts into the hot soup for a delightful finish. This cozy, flavorful soup is perfect on a chilly day and requires minimal hands-on time: set the slow cooker and return when it’s ready.
Crock-Pot Tomato Soup Recipe
Tomato soup made in the slow cooker is full of flavor and effortless. Unlike stovetop versions that need constant attention, this slow cooker method lets the ingredients simmer away while you handle other tasks. The result is a rich, aromatic soup you can easily customize. I like to finish it with thin leek slices for a bit of texture and grated cheese for extra creaminess.
What do you need for Slow Cooker Tomato Soup?
Below is an overview of the ingredients used in this recipe; exact amounts are shown in the recipe card.
- Tomatoes – Use fresh tomatoes in summer for the best flavor, or canned whole peeled tomatoes outside of tomato season. Canned tomatoes are usually picked and preserved at peak ripeness and can be tastier off-season.
- Vegetable stock – Use stock cubes or homemade vegetable broth. Chicken stock can be substituted if not serving vegetarian guests.
- Celery, onion, and carrots – These aromatics build a flavorful base for the soup.
- Butter and flour – Used to make a roux to thicken the soup and create a smooth, creamy texture.
- Tomato paste – Adds concentrated tomato flavor; briefly frying it before adding to the slow cooker mellows acidity and intensifies sweetness.
- Thyme, bay leaf, and basil – Fresh basil is great when available; dried herbs also work. These herbs deepen the soup’s flavor.
- Milk – Mixed into the roux to make a smooth sauce that enriches the soup.
- Leek – Very thinly sliced and added as a fresh topping after pureeing; the hot soup will wilt the leek slightly while retaining a pleasant bite.
- Grated cheese – Sprinkled on top to melt into the soup. Gouda or Cheddar melt well; Parmesan adds flavor but does not melt as smoothly.
How to prepare this crockpot tomato soup recipe
A printable recipe card with exact quantities and step-by-step instructions is included below. The basic process is simple:
- Melt butter in a skillet and sauté the diced onion, carrots, and celery for about 1 minute, stirring constantly. Add tomato paste and cook for another 2 minutes to deepen its flavor.
- Transfer the sautéed vegetables and tomato paste to the slow cooker.
- Add tomatoes (quarter fresh tomatoes or add canned whole tomatoes) and pour in the vegetable stock or water, according to your chosen liquid base.
- Add herbs: thyme, basil, and a bay leaf on top. Cover and cook on high for about 3 hours (or low for around 6 hours).
- Remove the bay leaf and purée the soup with an immersion blender until smooth.
- Make the roux: melt butter in a small pan, add flour all at once and cook while stirring for about 2 minutes to remove raw flour taste. Gradually whisk in cold milk to form a smooth sauce.
- Stir the roux into the pureed tomato soup, mix well, and adjust seasoning with salt and pepper to taste.
- Ladle into bowls and top each serving with thinly sliced leek and a generous sprinkle of grated cheese so it melts into the hot soup. Serve immediately with crusty bread, garlic bread, or a cheese sandwich.
If you try this recipe, tag your photo with #byandreajanssen on Instagram—I love seeing how you serve it. If you enjoyed the recipe, please leave a rating in the recipe card; it helps other home cooks discover it.
For more inspiration, you can find additional recipes and video tutorials by the same author in the recipe archive and video content sections on the original site.
📖 Recipe
Equipment
- slow cooker
- immersion hand blender
Ingredients
Crock-Pot Tomato Soup
- 1 tablespoon butter
- 2 stalks celery, washed and cut into small cubes
- 1 cup carrots, cut into cubes
- 1 onion, finely chopped
- 2 tablespoons tomato paste
- 56 oz. whole peeled tomatoes (2 cans) or about 2½ pounds fresh tomatoes in season
- 2 vegetable stock cubes or 3 cups fresh vegetable stock (ensure total liquid equals 3 cups)
- 3 cups water (if using stock cubes)
- 1 teaspoon dried thyme
- 1 bay leaf
- ½ oz. fresh basil
Roux
- 2 tablespoons butter
- 2 tablespoons flour
- 2 cups full milk
- Salt and pepper to taste
Topping
- 4 oz. grated cheese (Gouda or Cheddar)
- 4 oz. leek, finely sliced
All amounts are shown in metric and US customary units in the recipe card.
Instructions
Crock-Pot Tomato Soup
- Melt butter in a pan and sauté celery, onion, and carrot for about 1 minute.
- Add tomato paste and fry for another 2 minutes to deepen the flavor.
- Transfer the sautéed vegetables to the slow cooker.
- Add the tomatoes, stock cubes (or fresh stock), and water if needed. Break the tomatoes with a wooden spoon.
- Stir in thyme and basil. Place a bay leaf on top, cover, and cook on high for 3 hours (or low for 6 hours).
- Remove the bay leaf and purée the soup with an immersion blender until smooth.
Roux
- Melt butter in a pan over medium heat and add the flour all at once.
- Stir and cook the flour for about 2 minutes to remove the raw taste.
- Whisk in the milk gradually until you have a smooth sauce.
- Pour the roux into the slow cooker, mix well, and season with salt and pepper to taste.
To serve
- Ladle the soup into bowls, top with thin leek strips and grated cheese so it melts into the hot soup.
- Serve immediately with crusty bread, garlic bread, or a grilled cheese sandwich.
Notes
1. Tomatoes: Use about 2½ pounds fresh tomatoes in season. Use canned tomatoes when fresh ones lack flavor.
2. Vegetable stock: If using fresh stock, make sure the total liquid still equals approximately 3 cups.
3. Seasoning: Taste and adjust salt and pepper after adding the roux—broth saltiness varies and can concentrate during cooking.
4. Slow cooker timing: High for 3 hours yields good results; low takes about 6 hours.
5. Storage:
- Refrigerator: Cool quickly, cover, and store up to 2 days.
- Freezer: Cool quickly, leave about ½ inch headspace in an airtight container, and freeze for up to 2 months. Thaw in the refrigerator.
- Reheating: Warm over low heat, stirring occasionally until heated through.
6. Nutrition: Nutritional values are per serving, assuming six servings from the recipe.
Nutrition
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