This low-carb tomato sauce recipe is so simple to prepare and leaves you ample room to riff, whether you prefer making use of fresh tomatoes at peak season (and please do) or choosing a canned variety. It's a basic low carb marinara sauce - one without any added sugars (which is very common in many sauces you'll find at the grocery store) yet still has a punch of flavor from the fresh garlic and onions.
I feel there are two kinds of tomato sauce people: those who like simple tomato-based marinara and those who fall into the double-up-on-the-garlic camp. Is there an in-between? I'm not so sure.
Wherever your taste buds place you on the tomato sauce flavor spectrum, this simple low-carb tomato sauce recipe will work for you, I know it.
Omit the onions or garlic or herbs if you're a tomato sauce purist, or load it up with extra if that's what you love most.
The best thing about homemade tomato sauce is that it can be prepared in advance and stored in the fridge or freezer to have on hand.
Unlike my keto spaghetti sauce recipe (a tasty meat sauce!) this is a basic keto marinara sauce recipe that relies on simple ingredients. Which means it's incredibly versatile.
- easy to make and ready in 30 minutes
- free of any added sugar
- keto diet friendly, gluten free and dairy free/vegan
- simple to store
- super flavorful!
You can prepare this low-carb marinara sauce with fresh whole tomatoes or with canned tomatoes. The major difference I find is that fresh tomato sauce might need to simmer a bit longer to reduce.
Since the tomatoes are the main ingredient, make sure they're good ones!
Choose bright red tomatoes that are at their ripest. And if you're using canned tomatoes, San Marzano diced tomatoes (sometimes found with Italian herbs added) will give you the best flavor.
You will need:
- olive oil
- medium onion, chopped small
- minced garlic
- fresh tomatoes or canned San Marzano tomatoes (diced)
- tomato paste
- dried basil (or use fresh basil if you have it)
- dried oregano
- salt and black pepper
- butter or vegan butter (I like the flavor and ingredient list of this one) or more olive oil (optional)
Many of these ingredients are optional- certainly the garlic, onion, and even the herbs. I often use dried herbs for simplicity's sake (and they also hold up better for storing) but feel free to swap in fresh herbs if you have them (double up on the amount).
While many store-bought sauces use sugar, it's not really a must for a good tomato sauce. However, if the sauce tastes a bit acidic (this can vary based on your tomato ripeness and variety), a small amount of liquid monk fruit sweetener, stevia, or even a powdered keto-friendly sweetener will cut through that acidic taste and still keep this a sugar-free tomato sauce.
A swirl of butter added at the end is also the secret ingredient for mellowing out the acidity and adding a richness to the smooth sauce.
This low-carb tomato sauce recipe takes only minutes to prep- the rest of the time is spent allowing the sauce to simmer into rich, flavorful goodness.
- Sauté the onion and garlic. In a medium saucepan, cook the chopped onion in the olive oil over medium heat for about 5 minutes. Stir in the garlic and cook for another minute.
- Combine and cook. Add in the diced tomatoes (with their juices), tomato paste, herbs and salt and pepper. Stir to combine. Bring the mixture to a boil, then turn down the heat to a simmer. Cook for about 25-30 minutes. You can simmer the sauce for up to 45 minutes if you feel it needs to reduce longer (sometimes necessary with extra juicy ripe tomatoes). Stir occasionally and use your spoon to break down any large tomato chunks for a smooth sauce (or leave them if you prefer a chunky sauce).
- Stir in the butter or olive oil. A little bit of butter or olive oil added at the end will help cut through the acidity of the tomato sauce and give it a really rich and balanced flavor. I have tried this with both butter and a vegan buttery spread and I can't tell the difference. Swirl it in at the end, after the sauce has been removed from heat.
- Blend (optional). Depending on your preference, you can blend the sauce to make it a lot more smooth. I usually blend half the batch, then stir it back into the rest of the sauce. It ends up a little bit chunky but is still easy to spread onto a pizza.
tips for the best results
- The dried herbs can be substituted with dried Italian seasoning. If using fresh herbs, double up on the amount and adjust to taste.
- Net carbs in tomato sauce: This low carb tomato sauce recipe only contains 3 g net carbs and 4 grams of sugar, all of which are natural sugars from the tomatoes.
- To store: Once the sauce is cool, store it in glass jars (or a similar airtight container) in the refrigerator (5-7 days) or transfer ½ cup - ¾ cup portions into freezer-safe bags and freeze to store.
frequently asked questions
Tomato sauce can absolutely be incorporated into a keto or low-carb diet, especially when it's homemade since you'll have more control over what's in it.
It is not hard to find store-bought tomato sauces that do not include added sugars (Raos, for instance), but they are often at a higher price point. This low carb tomato sauce recipe is incredibly affordable and makes the most of tomatoes during peak season.
If you want a sweeter sauce, acceptable sugar replacements include liquid monk fruit sweetener, liquid allulose, or a powdered sweetener of choice.
Agave will also work well, especially because you won't a need a whole lot. I prefer liquid sweeteners since they're easy to stir in, add to taste, and won't leave a grittiness in the sauce (some granulated keto-friendly sweeteners don't dissolve as well as sugar).
Baking soda is another ingredient that can help cut through the acidity of tomato sauce. Stir in ¼ teaspoon and increase as needed.
Whether you're making a keto tomato sauce with fresh tomatoes or you need a go-to low-carb pizza sauce recipe, this is the one to save. It's a do-all-things, multi-purpose tomato sauce that will be enjoyed year-round, even after the last tomato harvest of summer.
you might also love...
- This 5-minute keto ranch dressing recipe. It's creamy, zesty and completely dairy free.
- Sunflower cashew ricotta, a low carb and vegan take on creamy ricotta cheese.
- Simple cauliflower risotto, made with crisp asparagus pieces and salty bacon.
- Turkish eggplant casserole, a low-carb and vegan casserole recipe that's loaded with spices.
- Keto Tuscan soup with beef and vegetables! A one-pot meal that's hearty and packed with flavor.
- 2 tablespoons olive oil
- 1 medium onion, chopped small
- 1 teaspoon minced garlic (add 2 teaspoons for more garlic flavor)
- 3-½ cups fresh tomatoes, diced OR 28 oz. canned San Marzano tomatoes, diced (with juices)
- 1 tablespoon tomato paste
- ½ teaspoon salt
- ½ teaspoon pepper
- 1 teaspoon dried basil
- 1 teaspoon dried oregano
- 2 tablespoons butter, vegan butter or olive oil
- Set a medium saucepan on the stovetop over medium-high heat and warm 2 tablespoons of olive oil. Add the chopped onions and cook for about 5 minutes to allow them to soften.
- Stir in the minced garlic and cook another minute.
- Add in the diced tomatoes (with their juices), tomato paste, basil, oregano, and salt and pepper. Stir to combine.
- Bring the mixture to a boil, then turn down the heat to low and let the sauce simmer for about 35-30 minutes (if using fresh tomatoes, it may need to simmer for up to 45 minutes to reduce). Stir occasionally and use your spoon to break down any large tomato chunks.
- Remove the sauce from the heat and swirl in 2 tablespoons of butter (vegan butter or more olive oil works well too). Taste and adjust, adding more salt if needed.
- Optional: Transfer half the sauce to a blender or food processor. Pulse a few times until it is smooth. Pour it back into the pan with the other half batch of sauce. Stir to combine.
- Serve immediately or allow it to cool completely before storing.
The small amount of butter or olive oil added at the end will help cut through the acidity of the tomato sauce and give it a really rich and balanced flavor.
Blending the sauce is entirely optional. If you prefer a chunkier tomato sauce, skip this step. I usually blend only half the sauce but you can blend the entire batch for an extra smooth sauce.
To store: Transfer the sauce a glass jar and keep in the refrigerator for up to 7 days. To freeze, transfer ½ cup - ¾ cup portions into freezer-safe bags.
If using fresh herbs, double the ingredient amount and adjust to taste.
If you'd like a sweeter sauce, add in liquid keto sweetener (like stevia, monk fruit drops, or liquid allulose) to taste.
Nutrition Information:Yield: 6 Serving Size: 1
Amount Per Serving: Calories: 102Total Fat: 7gSaturated Fat: 2gTrans Fat: 0gCholesterol: 15mgSodium: 27mgCarbohydrates: 7gNet Carbohydrates: 4gFiber: 3gSugar: 4gProtein: 2g
This nutritional information is approximate and is provided for convenience as a courtesy.