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Slow Cooker Tomato Soup

Slow cooker tomato soup is velvety and rich with irresistibly sweet tomato flavours. Simply add the ingredients to the slow cooker at breakfast time for an appetising and healthy lunch!

A bowl of Slow Cooker Tomato Soup with fresh crusty bread.

Slow Cooker Cream of Tomato Soup

Whilst creating the perfect slow cooker tomato soup recipe the obvious question was “do I use fresh or tinned tomatoes”?! After much testing, I found that tinned tomatoes work fantastically well for tomato soup and they have the added benefit of removing the need for any preparation or pre-roasting of tomatoes. What’s more, you also can be assured that the recipe will taste the same every time, which is always a win!

This recipe is everything a tomato soup should be. It has a rich tomato flavour with a hint of sweetness, a sumptuous texture and a little creaminess. As it’s made in the slow cooker in just four hours it’s the perfect option for lunch. I simply add everything to the pot first thing in the morning, and then look forward to an appetising, healthy lunch!

Overhead view of a bowl of Slow Cooker Tomato Soup with bread and butter.

What You’ll Need

Here’s what you need to make an easy tomato soup in the slow cooker. The full list of ingredients with quantities can be found in the recipe card at the bottom of the post.

  • Tomatoes – Tinned, peeled plum tomatoes work best and I opt for the best quality tinned tomatoes I can. I find that this really makes a difference with their flavour and natural sweetness.
  • Sweet Potato and Carrots – I confess, I really like the consistency of certain well-known brands of canned cream of tomato soup and tried to emulate it with this recipe! I find that adding root vegetables helps to achieve that delicious naturally sweet flavour and thick velvety texture.
  • Onion – Provides a savoury balance to the tomatoes.
  • Seasoning – I use vegetable stock cubes, garlic powder, celery salt, paprika, salt, pepper and dried basil to season the soup. I like to use dried basil because it’s convenient and provides a lovely subtle flavour. If you are using fresh basil leaves, about 10 large leaves will be enough as their flavour is more intense.
  • Milk – Milk is a perfect balancer of tomato acidity in soups, ragùs and sauces, reducing any tartness.
  • Sugar – A small amount to compliment the tomatoes.


Slow Cooker – As a guide, this recipe makes 1.5 litres of soup and so any slow cooker with greater volume than this amount will be fine. I use a 5L DuraCeramic Crockpot.

Jug Blender or Stick Blender – I have the Kenwood MultiPro food processor and I use the jug attachment for blending my soup. A hand-held stick blender will also work.

How To Make Slow Cooker Tomato Soup

It takes around five minutes to prep the ingredients and add them to the slow cooker, then a few minutes more to blend the soup mixture once it’s cooked. It’s that easy! Here are the steps:

Image displaying the six steps to make tomato soup in the slow cooker.
  1. Peel and chop the onion, carrot and sweet potato and place in the slow cooker.
  2. Add all of the remaining ingredients, apart from the milk.
  3. Stir well and cook on high for 4 hours.
  4. Check the vegetables are soft and then add the milk then cook on high for a further 15 minutes.
  5. Next, transfer the soup mixture to a jug blender and pulse until smooth. You can also do this with a stick blender directly in the slow cooker.
  6. Serve immediately or allow to cool and store in the fridge or freezer.

Serving Suggestions

As with any soup, Slow Cooker Tomato Soup tastes wonderful served with fresh crusty white bread and butter, or any bread for that matter! I sometimes like to scatter a little grated cheese on the top.

If you are entertaining guests and wish to serve it as an appetiser, why not swirl a little cream through the top and garnish with chopped parsley for a more decadent look?

Close up image of a spoon in a bowl of Crockpot Tomato Soup.

Top Tips

  • Dice the vegetables into 2cm chunks to ensure that they are cooked through within the cooking time.
  • Take the cooking times as a guide as there can be variances due to different brands and sizes of slow cooker.
  • Add the milk or cream at the end of the cooking time to prevent it splitting in the tomato and vegetables juices during cooking.
  • Ensure all of the vegetables are fully blended together to make the soup smooth and velvety. This may involve switching off the blender half way through and stirring to release any pieces that may have caught under the blades.
  • If blending the soup directly in the slow cooker with a stick blender, ensure that the blender is under the surface of the soup at all times to prevent any splatters of hot soup.
  • This recipe makes a thick soup, if you would prefer a thinner consistency then add more water or milk. Start by stirring in 100ml of extra liquid and checking the texture.
  • If you’re using fresh tomatoes, roast them before adding to the slow cooker to increase their depth of flavour.


How to thicken tomato soup in the slow cooker?

Adding root vegetables like carrots and sweet potatoes is a great and healthy way to thicken tomato soup. Alternatively, if the soup is looking watery after the stated cooking time then turn the slow cooker to high and lift and tilt the lid of the pot to leave a 2cm gap then cook for a further 30minutes. This allows steam to escape and the liquid quantity to reduce.

How many calories are in tomato soup?

There are around 120 calories to a 375ml serving of this tomato soup.

How long will tomato soup stay fresh for?

Homemade tomato soup will stay fresh in the fridge in an airtight container for up to three days. It can also be frozen for up to six months. Thaw and reheat thoroughly before serving.

What can I do with left over Slow Cooker Tomato Soup?

This soup is delicious reheated and served the next day however it also tastes great as a simple and tasty pasta sauce. Reheat the soup and melt in a few tablespoons of grated Parmesan or mature cheddar before serving over freshly cooked pasta!

Recipe Variations

Here are some ideas of simple adjustments or additions to this recipe.

  • Fresh tomatoes – Fresh tomatoes taste best if they are pre-roasted in the oven and the heat also allows their skins to be easily removed. Simply cut them in half, place them on an oven tray, drizzle with oil and roast on a medium to high heat for 15-20 minutes. Use these in place of the canned tomatoes in the recipe. Note that you may need to make adjustments to the volume of milk and sugar in the recipe to balance any variances in sweetness and acidity .
  • Chopped tomatoes – You can use chopped tomatoes but be aware that these are more processed and tend to have a higher water content.
  • Potato – Sweet potato thickens and provides a subtle sweetness to this soup. You can use a large white potato in it’s place, peeled and diced. A waxy, low starch variety works best.
  • Milk – I achieve the creamy flavour of this tomato soup using either whole or semi-skimmed milk. I find that fully skimmed milk (red top milk here in the UK) doesn’t cut through the acidity of the tomatoes to the same degree.
  • Cream – Use single cream in place of milk for a more decadent taste, start by adding 2/3rds of the stated recipe amount of milk and test for taste
  • Seasoning – Add half a teaspoon of dried, ground chilli powder to add heat to the soup.
  • Homemade Tomato and Basil Soup – This recipe can be adapted to make a deliciously fresh tasting homemade tomato and basil soup. Simply half the quantity of milk stated in the recipe card and double the amount of dried or fresh basil.
Close up image of a bowl of Slow Cooker Tomato Soup and crusty white bread.
Overhead view of Slow Cooker Tomato Soup in a bowl with bread.

Slow Cooker Tomato Soup

Slow cooker tomato soup is velvety and rich with sweet tomato flavours. Put this in the slow cooker at breakfast time for an appetising and healthy lunch!
5 from 12 votes
Prep Time 10 mins
Cook Time 4 hrs 15 mins
5 mins
Total Time 4 hrs 30 mins
Course Appetizer, Main Course
Cuisine British
Servings4 people


  • 250 g (2 cups) Sweet Potato peeled and diced. This equates to roughly one baking sized potato. Use white potato as an alternative.
  • 150 g (1.2 cups) carrots equates to two medium carrots, peeled and chopped.
  • 2 400g (30 oz) canned tomatoes peeled plum tomatoes
  • 1 white onion
  • 4 tbsp tomato puree
  • 2 vegetable stock cubes
  • 1 tsp dried basil
  • 1 tsp paprika
  • ½ tsp garlic granules
  • ½ tsp celery salt
  • ½ tsp sugar
  • 150 ml (0.65 cups) milk
  • 250 ml (1 cups) water
  • pinch of ground black pepper


  • Peel and dice the vegetables into chunks of around 2cm or less. Add these to the slow cooker.
  • Add all of the remaining ingredients apart from the milk. Stir everything together.
  • Cook on high for 4 hours or low for 6 hours.
  • Check that the soup mixture is completely cooked through. The onions will be translucent and the vegetables can be easily sliced through with a knife. Then add the milk and cook for a further 15 minutes on high.
  • Next, carefully transfer the soup mixture to a jug blender and pulse until smooth. You can also do this with a stick blender directly in the slow cooker.
  • Serve immediately or allow to cool and store in the fridge or freezer.


Chopped Vegetables

Dice the vegetables into chunks no larger than 2cm to ensure that they are cooked through within the cooking time.

Blending The Soup

Once cooked, the soup will be hot. Take care when blending with a stick blender, or when transferring to a jug blender.

Cooking Time

If required, the soup can be cooked for longer than four hours.
Different brands and sizes of slow cookers operate at different temperatures. The stated cooking times should be used as a guide only.

Soup Thickness

This recipe makes a thick soup. If you prefer a thinner consistency, stir in milk or water in 100ml increments.


Calories: 121kcalCarbohydrates: 24gProtein: 3gFat: 2gSaturated Fat: 1gPolyunsaturated Fat: 1gMonounsaturated Fat: 1gCholesterol: 4mgSodium: 717mgPotassium: 515mgFiber: 4gSugar: 9gVitamin A: 15524IUVitamin C: 8mgCalcium: 92mgIron: 1mg
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