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slow-cooker-spaghetti-sauce-in-freezer-containers in storage containers

Tomato Sauce from Fresh Tomatoes (in the Slow Cooker)

Amy Palanjian
This tomato sauce method is the easiest way to transform fresh tomatoes into delicious sauce. Scale the recipe up or down for a smaller or larger slow cooker. You don't have to be precise! And the chopped tomatoes can be very roughly chopped.
5 from 5 votes
Prep Time 15 mins
Cook Time 8 hrs
Total Time 8 hrs 15 mins
Course Dinner
Cuisine American
Servings 10 (or 2 quarts)
Calories 83 kcal


  • 4 quarts fresh tomatoes (very roughly chopped with stems discarded)
  • 4 garlic cloves (peeled)
  • 1 teaspoon dried oregano
  • 1 teaspoon salt
  • 1/2 cup fresh basil leaves
  • 1 tablespoon olive oil


  • Fill the slow cooker with chopped fresh tomatoes, stems discarded, and the garlic. Cover and cook on low overnight, or for about 8-10 hours. 
  • Remove the lid and let cool for 30-60 minutes. (This makes it possible to blend them without the risk of the steam making your blender explode. Which is key.)
  • Use a large slotted spoon or small mesh spoon to scoop out the tomato solids and garlic into a blender, leaving the liquid in the slow cooker.
  • Add oregano, salt, olive oil, and basil and blend into a smooth sauce. (You may need to do two batches.) Blend very, very well to ensure that the skin is blended up.
  • Pour into freezer containers or storage bags and freeze for up to 1 year. Thaw overnight in the fridge. (Don't worry if it looks a little separated—it will come back together when it's warmed up.)
  • To use, heat a pot over medium heat, add sauce, and simmer for 10-15 minutes. 


  • You can leave the peel on the tomatoes. It blends in when you puree the sauce in Step 3.
  • Cut the amounts in half if you have a smaller amount of tomatoes.
  • If you don't have fresh basil, you can omit it. Add 1/2 teaspoon dried Italian seasoning if desired instead.
  • Once cooked, let the tomatoes cool enough that you can safely blend them. If they are too hot, the steam may cause the top of the blender to come off (and trust me, you don't want that!). Blend the sauce in two batches to help eliminate the possibility of this even more.
  • Let cool before storing the containers in the fridge or freezer.
  • Thaw in the fridge or at room temperature.
  • Season the sauce to taste with salt and pepper before you toss it with the pasta.


Calories: 83kcalCarbohydrates: 15gProtein: 3gFat: 2gSaturated Fat: 1gPolyunsaturated Fat: 1gMonounsaturated Fat: 1gSodium: 252mgPotassium: 908mgFiber: 5gSugar: 10gVitamin A: 3220IUVitamin C: 52mgCalcium: 46mgIron: 1mg
Keyword slow cooker spaghetti sauce, tomato sauce from fresh tomatoes
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