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Slow cooker tomato sauce.

Slow Cooker Tomato Sauce

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  • Author: Kelli Avila
  • Prep Time: 00:05
  • Cook Time: 08:00
  • Total Time: 8 hours 5 minutes
  • Yield: 1-1/2 quarts 1x
  • Method: Slow Cooker


This Slow Cooker Tomato Sauce, flavored simply with basil, onion and butter, is an easy, hands-off way to make a really flavorful sauce for pasta (and lots of other dishes too).


  • 2 (28 ounce) cans san marzano tomatoes
  • 4 tablespoons butter
  • 1 medium onion, peeled but left whole
  • 2 cloves garlic
  • 1 tablespoon kosher salt, more to taste
  • 1 tablespoon turbinado sugar
  • 3 sprigs of fresh basil
  • 1 teaspoon dried oregano


  1. Add all ingredients, to a large slow cooker and cook on high for 4-6 hours or low for 6-8 hours.
  2. Once done, remove the onion, garlic cloves and basil and discard.
  3. If desired, break up the tomatoes with a potato masher, or you can partially or fully puree the tomato sauce.
  4. Taste and adjust the seasoning, adding more salt when necessary.
  5. Serve as desired.


Why specifically San Marzano tomatoes? Simply because they offer the best flavor for this simple tomato soup using canned tomatoes. Most grocery stores will sell canned San Marzano, so be sure to grab them if you can to use in this recipe.

If your slow cooker has a tight fighting lid that prevents any evaporation, if you are able to, do not snap the lid closed. It’s best if the lid isn’t very tight fitting to allow some minor evaporation to occur.