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Overhead photo of Keto Marinara Sauce in a cast iron skillet garnished with parsley and sitting on a white background.
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5 from 7 votes

Keto Marinara Sauce Recipe

There is nothing quite like the cozy smell of this Low Carb Marinara Sauce simmering on the stove. It is perfect to make on a lazy Sunday afternoon.
Prep Time10 mins
Cook Time44 mins
Total Time54 mins
Course: Main
Cuisine: American, Italian
Keyword: comfort food, spicy
Servings: 16
Calories: 76.01kcal
Author: Wendy Polisi


  • ¼ cup unsalted butter
  • ¼ cup extra-virgin olive oil
  • ½ cup diced onion
  • 2 teaspoons minced garlic
  • 56 ounces canned whole peeled tomatoes 2- 28 oz cans crushed by hand (make sure you use a no-sugar added brand)
  • 1 tablespoon Italian seasoning
  • 2 teaspoons sea salt
  • 1 teaspoon fresh ground black pepper
  • ½ teaspoon crushed red pepper flakes


  • Heat butter and olive oil in a large stock pan to medium heat.
  • Add onion and cook for 4 minutes, until tender. Add garlic and cook for one minute longer.
  • Stir in tomatoes, Italian seasoning, salt, pepper and crushed pepper flakes.
  • Bring to a boil.
  • Reduce heat to low and cook for 40 minutes.



  • You can use 3 ½ pounds of fresh ripe tomatoes in place of the canned tomatoes.
  • If desired, stir in fresh basil and/or oregano in the last 10 minutes of cooking.
  • If you are low carb and not keto, a grated carrot added in when you add the onion adds a nice hint of sweetness.
  • Stir in 3 ounces of Parmesan cheese at the end.

Slow Cooker Keto Marinara Sauce

  1. Complete steps one and two on the saute' function of your slow cooker, or on the stovetop.
  2. Add all the ingredients to your slow cooker, and cook on low for 8 hours.

Instant Pot Keto Marinara Sauce

  1. Turn your Instant Pot to saute, and add the butter and olive oil to the pot.
  2. When the butter melts, add onion and cook for 4 minutes. Add garlic and cook for another minute.
  3. Stir in tomatoes, Italian seasoning, salt, pepper, and crushed pepper flakes.
  4. Close the lid, and make sure it is set to seal.
  5. Cook on high pressure for 10 minutes.
  6. Release the pressure using the quick-release method.
  7. Carefully unlock and remove the lid.


Calories: 76.01kcal | Carbohydrates: 4.89g | Protein: 0.93g | Fat: 6.41g | Saturated Fat: 2.32g | Cholesterol: 7.63mg | Sodium: 434.42mg | Potassium: 197.78mg | Fiber: 1.26g | Sugar: 2.6g | Vitamin A: 228.57IU | Vitamin C: 9.71mg | Calcium: 38.43mg | Iron: 1.11mg