4.89 from 9 votes
Delicious fat free slow cooker tomato sauce. Perfect for pasta and pizza.
Fat Free Slow Cooker Tomato Sauce (Marinara Sauce)
Prep Time
5 mins
Cook Time
8 hrs
Total Time
8 hrs 5 mins

This throw it all in and forget it recipe for a rich and intense fat free slow cooker marinara or tomato sauce will become a freezer staple. Perfect for pizzas or pasta, it's a simple slow cooker recipe that delivers scrumptious results every time. Gluten free and vegan. 

Course: Sauce
Cuisine: Italian, Slow Cooker
Keyword: slow cooker tomato sauce
Servings: 12 people
Calories: 27 kcal
Author: Helen Best-Shaw
  • 800 g canned tomatoes (2 cans)
  • 3 medium tomatoes (roughly chopped)
  • 1 small onion (peeled and roughly chopped)
  • 3 garlic cloves (peeled and sliced in half)
  • 2 tbs tomato puree
  • 2 stalks fresh basil
  • pinch dried oregano
  • salt and pepper (to taste)
  1. Simple pop all the ingredients into your slow cooker, and stir.

  2. Cook on low, with the lid on, for about 8 hours or overnight.  If needed cook for another hour or two with the lid of the slow cooker slightly ajar to reduce further.

  3. Blitz to a smooth sauce with a stick blender. 

  4. Allow to cool before packing into tubs, glass jars or ice cube trays ready for freezing.

Recipe Notes

This is such an adaptable recipe and really is as simple as throwing it all in the slow cooker and leaving it to cook.

For a touch of heat add a pinch of chilli powder - take care though as the long slow cooking will intensify the heat.

You will get better results from using a mid range brand of canned tomatoes, not the most expensive, but not the cheapest which can be watery and taste metallic.

Freezes well.

All slow cookers behave differently, the sauce may need more or less time depending on the wattage and if your cooker has any hot spots.

Nutrition Facts
Fat Free Slow Cooker Tomato Sauce (Marinara Sauce)
Amount Per Serving
Calories 27
% Daily Value*
Sodium 89mg4%
Potassium 236mg7%
Carbohydrates 6g2%
Fiber 1g4%
Sugar 3g3%
Protein 1g2%
Vitamin A 240IU5%
Vitamin C 8.2mg10%
Calcium 25mg3%
Iron 0.9mg5%
* Percent Daily Values are based on a 2000 calorie diet.