Keto Marinara Sauce

Easy Keto Marinara Sauce is perfect with your favorite low-carb pasta, on pizza, or in a casserole. You won’t go back to store-bought after trying this! Simmered to perfection, this low carb tomato sauce is a great way to add flavor. This easy Sugar Free Spaghetti Sauce Recipe takes less than 5 minutes to prep.

We love all sorts of Italian dishes at our house, and having a really great quality sugar free spaghetti sauce recipe is a must. The entire family loves the flavor, and they don’t even care or realize it’s low-carb. They will eat it without complaint, and that leaves me pretty happy too.

I also love how versatile this low carb keto marinara sauce is. You can use it for so many different recipes, and it tastes delicious. Dipping these Keto Breadsticks into the sauce is one of our favorite sides for dinner. 

If you are looking for more great keto sauces, try my Alfredo Sauce with Basil and Vodka Sauce Recipe.

Ingredients

• Canned San Marzano Tomatoes – Canned San Marzano tomatoes are a popular choice for their rich flavor and natural sweetness. They make a delicious base for this homemade keto marinara sauce. You can find them at most grocery stores, and canned whole peeled tomatoes work well if San Marzano tomatoes aren’t available.
• Salted Butter – Adding salted butter to spaghetti sauce enhances the flavor and richness. It also helps balance the acidity of the tomatoes, giving the sauce a slightly creamy texture without adding cream.
• Onion – To enhance the flavor and add a subtle sweetness to my spaghetti sauce, I always include a whole halved onion. As the sauce simmers, the onion releases its flavor into the tomatoes. I remove it at the end, but you can save it for another recipe.
• Salt & Pepper – Adding salt and pepper to spaghetti sauce brings out the flavor of the tomatoes. I like to taste the sauce after simmering and adjust the seasonings as needed.
• Sweetener – Adding a sweetener to spaghetti sauce helps balance the acidity of the tomatoes. This is optional, so taste the sauce before adding any.

See quantities in the recipe card.

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How To Make Keto Marinara Sauce

This is one of the simplest low-carb marinara sauce recipes ever. Mostly, you add in the ingredients, stir it every once in a while, and it does the work for you. Let’s take a look:

First Step: Add the tomatoes, onions, butter, salt, and pepper to a pot on the stovetop over medium-low heat. Stir to prevent sticking and let it simmer for one hour.

Second Step: After the hour is up, you can take the onions out of the pan. Either add them to another recipe or discard them. Add any extra salt and pepper that you want, as well as any sweetener that you like. You can also add fresh basil to the keto spaghetti sauce recipe to taste as well. 

👉 Expert Tip: That onion that was simmered in the sauce is delicious. I like to chop it up and use it in Keto Meatballs, a casserole, or my Keto Turkey Meatloaf!

Variations

This is an easy recipe to customize to fit your taste buds. Here are a few ideas you might like to try out to customize this sugar free spaghetti sauce recipe:

• Garlic – Add 1-2 cloves of minced fresh garlic to the sauce if you love garlic. Adding in roasted garlic is even better! You can also use garlic powder if you don’t have fresh garlic on hand.
• Oregano – If you love oregano, you can add fresh or dried to the marinara sauce. Just add as much as you like to flavor it. 
• Red Pepper Flakes – If you like a little bit of spice in your sauce, feel free to add a dash or two of crushed red pepper flakes. Don’t go overboard and make it too spicy, but just add a little bit. 
• Italian Seasoning – You could add a teaspoon or so of your favorite Italian seasoning to enhance the flavors too. 
• Onion Powder – If you want a stronger onion flavor, add a pinch of onion powder along with the other spices.
• Crushed Tomatoes – You can substitute canned crushed tomatoes for the whole tomatoes if you prefer a more uniform sauce without blending.

Equipment

All you need for this easy keto marinara sauce recipe is a large saucepan or pot and a spoon for stirring. An immersion blender is optional if you want a smoother texture.

Storage

The low carb spaghetti sauce will last around 4 days if kept in the fridge. Let it cool down before putting it in the fridge. You should keep it in an airtight container or jar with a lid.

Another idea would be to make an extra-large batch or two and let it cool. Once cooled, pour the sauce into some freezer-safe ziplock bags. Don’t fill them to the top, just about ⅔ full to make room for the sauce to expand. Remove any excess air, lay flat, and put in the freezer. The low carb marinara sauce will keep for about 3 months for the best quality. You can warm it up in a saucepan or in the microwave when ready to eat it.

Common Questions

Why Do You Put Butter in Marinara Sauce?

Using butter instead of extra virgin olive oil gives the sauce a slightly creamy note that is delicious. You may not believe it but I got the idea for this sauce from a Nicholas Sparks novel. One of the characters makes a similar sauce and ever since I read that book 10 years ago I’ve made this version of it.

Why Should I Make My Own Sauce?

There are several reasons to make your own keto pasta sauce recipe at home. First of all, you will know every ingredient that goes into the sauce. There are no surprises, and you already know that there’s no added sugar unless you choose to add sweetener. Some store-bought sauces contain added sugar, so making your own lets you control the ingredients and carbohydrates.

Secondly, it’s a frugal way to save some money. You can very inexpensively make gluten free homemade marinara sauce and have so much more than what comes in a jar from the market. I get the appeal of buying it pre-made, but honestly, this comes together so FAST, and it’s mostly hands-off.

Does This Marinara Sauce Need Sweetener?

This is completely up to you whether or not you want to add sweetener to the low carb pasta sauce recipe. I recommend preparing the sauce and tasting it before deciding. Tomatoes are typically fairly sweet, so adding sweetener may make it too sweet for your tastes. Whatever you like is going to be the right answer to create your own favorite pasta sauce recipes.

Ways to Use Keto Marinara Sauce

There are many ways to use low carb marinara sauce in your favorite keto recipes besides just pouring it over your favorite keto pasta noodles or zucchini noodles or using as pizza sauce. Serve homemade spaghetti sauce on spaghetti squash with some Instant Pot Turkey Meatballs or Italian sausage for a quick meal.

I use this in my Keto Pizza Casserole, on Keto Chicken Parmesan, and even as a base for tomato soup. You can use it in any recipe that calls for pasta sauce. For a vegetarian choice, try it in my Eggplant Gratin or Cauliflower Parmesan. There is something about Italian food that equals comfort food to me.

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Originally Published August 10, 2020. Revised and Republished October 21, 2026.