This is the sauce I reach for when a recipe calls for marinara, and I do not want to check a jar label for hidden sugar. Keto tomato sauce gets its richness from an unlikely source, and it takes about an hour in the oven with almost no attention needed.
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I always make a double batch, since this freezes well and having it on hand saves a trip to the store on a busy night. The surprise ingredient is butter. It builds a depth of flavor that usually takes hours of stovetop simmering to get to, without standing over the pot.
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Chef Jenn’s Take on Keto Tomato Sauce
Most homemade tomato sauce recipes ask for an hour or more of stovetop attention, stirring and watching so it doesn’t scorch on the bottom of the pot. That kind of time commitment is why so many people default to a jar instead, even knowing most jarred sauces carry added sugar.
This version skips the stovetop entirely. Canned tomatoes go into a deep, oven-safe dish, dotted with butter and scattered with smashed garlic, then into a hot oven for about an hour with just one or two stirs along the way. The butter is doing more work than any other ingredient here. It builds the same richness a long stovetop simmer usually creates, without needing to babysit the pot.
One reader reported good results making this in an Instant Pot instead, about 14 minutes at pressure with a natural release, and said it tasted like it had simmered for hours. I have not tested that version myself, so treat it as a reader-reported option rather than a confirmed method
What You’ll Love About Keto Tomato Sauce
- No hidden sugar or starch to check for, since you’re controlling every ingredient yourself.
- Four ingredients, one dish, and about an hour of mostly hands-off oven time.
- Freezes well, so a double batch means homemade sauce on hand for weeks.
Ingredients
- Canned tomatoes – Whole, crushed, or diced all work. Check the label for no added sugar.
- Butter – Salted, and don’t skip it. This is what gives the sauce its richness.
- Garlic – Fresh cloves, smashed rather than minced, so they soften and blend into the sauce as it bakes.
- Salt and pepper – To taste, added at the end once the sauce has reduced.
How To Make Keto Marinara SAuce
Scroll down for the full recipe card with exact measurements and printable instructions.
Empty the canned tomatoes into a deep, oven-safe dish. If you’re using whole tomatoes, crush them by hand or with a potato masher first.
Dot the top of the tomatoes with butter and scatter the smashed garlic cloves over everything.
Bake in a hot oven for about an hour, stirring once or twice partway through so it cooks evenly. Remove from the oven and mash any remaining chunks of tomato and garlic with the back of a fork or a potato masher. Season with salt and pepper.
Use right away, or cool completely before storing or freezing.
Pizza SAuce?
Another great use of this keto tomato sauce recipe is to turn it into pizza sauce. To the basic recipe, add 1 tsp dried oregano, 1 tsp dried basil, and 1 tsp garlic powder. Mix well and use like any pizza sauce.
Click on the carousel below for step-by-step pictures, or just follow along with the recipe, and in no time, you’ll have a batch of hot and tasty keto-friendly tomato sauce ready in no time!
Make It A Meal
This sauce is the base for my Sausage Parmigiana, and it’s worth keeping a double batch in the freezer just for that recipe alone. It also works well in Chicken Parmesan Lettuce Wraps if you want something lighter.
If you’d rather turn this into a pizza night, my Pizza Sauce recipe starts from this same base with a few added herbs.
Storage
Store in an airtight container in the fridge for up to 5 days. Reheat gently on the stovetop or in the microwave. This freezes well for up to 3 months, and freezing in flat bags makes it easier to thaw quickly. Thaw overnight in the fridge before using.
Frequently Asked Questions
This recipe runs about 3 net carbs per generous 1/3 cup serving. The number in the recipe card below will recalculate once this post is republished, so use it as an estimate until then.
Yes, one reader shared that she browns ground beef separately and stirs it in after the sauce is done, setting some sauce aside first for a vegetarian family member before adding the meat. That approach works well if you want a similar option.
No, this recipe is built entirely around oven roasting instead of stovetop simmering. The oven does the same job with much less hands-on attention.
Yes, this base recipe is meant to be adjusted. Dried oregano, basil, or a pinch of red pepper flakes all work well stirred in after baking.
Add Preferred SourceKeto Oven-Roasted Tomato Sauce
Ingredients
- 56 ounces canned tomatoes (2 28-ounce cans of whole, crushed, or diced)
- 1/2 cup butter
- 6 cloves garlic smashed
- 1 teaspoon salt or to taste
- 1/2 teaspoon pepper
Instructions
- Empty the two 28-ounce cans of tomatoes into an oven-safe shallow dish. I used a 13 x 11 pyrex dish for this dish. If the tomatoes are whole, crush them with your hands or a potato masher.
- Dot the top of the tomatoes with butter. Yes, butter! Butter adds unbelievable richness and flavor to this sauce. Add the garlic.
- Bake at 425-F for about an hour, stirring once or twice during the cooking time.
- Remove from the heat and using the back of a fork or a potato masher, mash up the remaining chunks of tomato and garlic. Season with salt and pepper, and use in your favorite dish.
Notes
Recipe Card Tips
- Don’t skip the butter or reduce the amount. It’s doing the work that a long stovetop simmer usually does, and the sauce tastes noticeably thinner without it.
- Check your canned tomatoes for added sugar or salt before you buy. Brands vary quite a bit here.
- Freeze in flat, single-layer bags instead of containers. Flat bags thaw faster and stack better in a crowded freezer.
Nutrition
A Note on Nutritional Information
Nutritional information for this recipe is provided as a courtesy and is calculated based on available online ingredient information. It is only an approximate value. The accuracy of the nutritional information for any recipe on this site cannot be guaranteed. Erythritol carbs (sugar substitutes) are not included in the carbohydrate counts as they have been shown not to impact blood sugar, and they have zero calories and zero carbs. Net carbs are the total carbs minus fiber.
Oh my gosh, this is so good!!! I made it tonight to have ready for a meal this upcoming week (although I haven’t decided exactly what yet) and immediately after tasting it my husband said, “oh, this is absolutely delicious! We need to use this ASAP!” 😁
Thank you for sharing!!
This oven roasted sauce sounds wonderful. Will be trying this. Thank you
I’ve made this in my insta pot (14 min, natural release) and it tasted like I cooked it for 3 hours. I had doubled the recipe, cooled the portion that I wanted to freeze before pouring into freezer bags. Lay flat to freeze. Awesome sauce!
this sauce is delicious. I have many complements on it!!!!
I’m so glad you like it, and thanks for stopping by to tell me! ~Jenn
What a fabulous recipe. I usually purchase LaVictoria marinara sauce; it’s lower in carbs than Rao’s, tastes better, and is less expensive. However. your recipe for roasted tomato sauce is clean. so tasty, and so inexpensive. It’s a winner 🏆
Wonderful, my husband’s favorite sauce. We add browned ground beef for spaghetti sauce. Yumm…. (we are saving some out before adding meat for our vegetarian daughter.)
I’m so glad you loved it, and thanks for coming back to leave a comment! ~Jenn