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Slow cooker tomato sauce is easy to make, and a great way to use up all those garden tomatoes!

Slow Cooker Marinara Sauce.

An easy recipe for slow cooker marinara sauce - this is a great sauce for pasta or breadsticks!
Course Entree
Cuisine gluten free, Italian, vegan.
Prep Time 20 minutes
Cook Time 5 hours
Total Time 5 hours 20 minutes
Servings 4 pints
Calories 237 kcal
Author The Pretty Bee


  • 25 large tomatoes
  • 1 large sweet onion chopped
  • 7 cloves garlic roughly chopped
  • 2 Tablespoons olive oil
  • 1 1/4 teaspoons salt
  • 1/2 teaspoon pepper
  • 5 teaspoons Italian seasoning
  • 3 teaspoons sugar


  1. Preheat the oven to 400 degrees. Line two rimmed cookie sheets with parchment paper.
  2. Core the tomatoes and slice in half. Roast for about 15-20 minutes, or until the skins wrinkle up.
  3. Remove from the oven and set aside until the tomatoes are cool enough to handle.
  4. Once the tomatoes are cool enough to touch, pull the skins off, and squeeze the seeds out.
  5. Place the peeled tomatoes in the slow cooker. Add the onion, garlic, olive oil, salt, pepper, Italian seasoning, and sugar.
  6. Cover and cook on low for 5-6 hours, or on high for 3 hours.
  7. Once the sauce is cooked, use an immersion blender to blend it to your desired consistency. I blend until it is completely smooth.
  8. If you aren't serving it right away, let it cool completely before refrigerating. You can also put it in freezer bags and freeze it. Makes 4 pints.
Nutrition Facts
Slow Cooker Marinara Sauce.
Amount Per Serving
Calories 237 Calories from Fat 72
% Daily Value*
Fat 8g12%
Saturated Fat 1g6%
Sodium 767mg33%
Potassium 1914mg55%
Carbohydrates 39g13%
Fiber 10g42%
Sugar 24g27%
Protein 7g14%
Vitamin A 6445IU129%
Vitamin C 109mg132%
Calcium 133mg13%
Iron 3.2mg18%
* Percent Daily Values are based on a 2000 calorie diet.