Slow Cooker Tomato Sauce

We currently have two weeks left of the summer holidays 2018. Don’t get me wrong, we have had a wonderful time as a family together creating memories, but I am ready to get back to more of a routine. My really long list of ideas at the beginning of the holiday has only been partially completed. However, my list was stupidly long and contained things that we were really never going to attempt to do. For example, bullying Simon into constructing a Wendy House out of all the wood scraps we have accumulated in the garden. Funnily enough this hasn’t been done yet!

I was looking for a wallet-friendly way to spend my Wednesday with the kids. An activity that I could fit around a trip to the park with Seb’s school friends and Ophelia’s swimming lesson. Then I remembered the slow cooker. We haven’t used it in a while and it would be perfect to fit around all the other little bits we had planned for the day.  As I was racking my brain for a recipe idea, I realised our supply of tomato ketchup was perilously low. This made me realise that we could in fact make tomato sauce in the slow cooker. Yes it is a rather labour intensive way to get a jar of tomato sauce, but the kids would have fun chopping vegetables and then mixing it all up.

Atticus cutting a tomato.
Seb cutting celery.

This recipe was excellent for improving knife skills for all the kids. The boys did a really good job with various knives for chopping different vegetables. Their confidence has really improved with frequent practice over the past 6 months. Ophelia, age 2, stuck with a table knife for chopping tomatoes and she is even holding the knife the right way around now!


  • 1 tin of chopped tomatoes
  • 500g tomatoes
  • 3 sticks of celery
  • 1 red onion
  • 2 cloves of garlic
  • Fresh ginger (about an inch long), peeled and grated
  • 1 bunch fresh basil
  • 2tsp ground coriander
  • 200ml red wine vinegar
  • 70g soft brown sugar
  • Seasoning


  1. Chop the vegetables and place into the slow cooker.
  2. Grate the ginger and add to the vegetables.
  3. Gently bash the garlic cloves with a wooden spoon to loosen the skin and remove it, then slice and add to the slow cooker.
  4. Add the tinned tomatoes.
  5. Pull the basil leaves off the stalks and add them to the pot.
  6. Measure out the red wine vinegar, brown sugar, and ground coriander and add to the mixtures.
  7. Season to taste and mix well.
  8. Turn the slow cooker on low and leave uncovered.
  9. After around 5 hours turn the cooker to high to help it fully reduce.
  10. Turn it off when the sauce looks very thick with little liquid remaining. This took ours around 3 hours.
  11. Allow to cool fully and then blend. (We blended it the following morning.) We found that a stick blender didn’t make it as smooth as we wanted it so ended up using the food processor to achieve a smoother ketchup.

This tomato sauce will keep for 2 weeks in the fridge or 2 months in the freezer. My recommendation would be store it in batches in the freezer if you don’t think that you will finish it all in 2 weeks as it really is too yummy to waste.

Ophelia is the tomato lover of our children. She loves them nearly as much as I do. The surprise was how much Atticus enjoyed the tomato sauce. As our resident ‘fussy eater’, he will often refuse tomatoes and will try and sneak them to his sister when I am not watching. But he devoured the ketchup on his homemade burger and chips and even asked for more!


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