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Roasted Tomato Marinara Sauce with Garlic, Onion and Basil

This robust Roasted Tomato Marinara Sauce with Garlic, Onion and Basil makes good use of in-season tomatoes and is perfect for freezing to enjoy later.

Confession: I keep glass jars and use them to store things. This old marinara jar was perfect for storing my homemade marinara sauce in the fridge or freezer.

When we planned our garden this spring, I knew I wanted enough tomatoes to make sauce. We planted big tomatoes for slicing, itty bitty tomatoes for snacking and paste tomatoes and other tomatoes for sauce.

Our harvest has been exciting and robust. We’ve eaten so many tomatoes that we grew in so many ways — just what I wanted. And we had so many, that could take some of the tomatoes and use them for a sauce.

A fresh roasted tomato marinara sauce. One that’s dotted with sweet sauteed onions and minced garlic. One that’s flavored with basil and oregano. Oh, this sauce is delightful.

It all begins with roasting tomatoes. This is four pounds of red and yellow tomatoes from our garden. You could use whatever tomatoes you want — of any color.

The tomatoes are roasted for an hour.

That releases the juices and loosens the skin … and gives them a richer flavor.

Once that’s done, I stick them in the fridge overnight — juices and all. They are much easier to handle cooled.

The next day, I run the tomatoes through my food mill. It’s a pretty basic machine with a hand crank that separates the juices and pulp from the seeds and skins. If you don’t have one, I’d recommend removing the skins by hand and pressing the flesh through a fine-mesh sieve.

Finally, it’s time to make the sauce. Onions are cooked in a pot for about 10 minutes until they are translucent and golden in places. Then add the tomato pulp and juices. Season, cook for a bit, and then stir in tomato paste and cook some more.

At the end, I swirl in a little baking soda to combat acidity. Just a little though — otherwise the sauce loses its edge.

About a third of the batch went into a container in the freezer. The rest we had with pasta and homemade turkey meatballs. It was delightful — a bright reminder of summertime.

I’m hopeful we might have enough tomatoes for another batch soon. Perhaps a few batches so we can stock the freezer? Paige also used some of our tomatoes to make pizza sauce as well.

This recipe isn’t for canning

But one thing I won’t be doing is canning this sauce. Did you know that the acidity of tomatoes isn’t great enough for safe water bath canning? In fact, over the last 50 years, changes in tomatoes have rendered them less acidic — so even if your grandmother always canned her sauce without any additions to it.

This isn’t to say you can’t safely can tomatoes or tomato products. You can. But you need to add an acid — such as bottled lemon juice — to increase the acidity just before canning.

That’s not the only reason I am not canning though. These cute jars from store-bought sauce aren’t made for canning. In fact, the glass is only approved for one sealing (the original one). But they are perfectly fine for freezing.

I could absolutely use a different jar and augment the sauce with lemon juice, but for this sauce, I just prefer to freeze it.

Yield: 3-4 cups

Roasted Tomato Marinara with Onions, Garlic and Basil

Roasted Tomato Marinara with Onions, Garlic and Basil

Fresh tomatoes are roasted, bringing out a robust flavor, and then combined with sauteed onions and garlic for a delightful, fragrant sauce.


  • 4 lbs fresh tomatoes, washed
  • 1 tbsp olive oil
  • 1 large Vidalia onion, diced
  • 6 cloves garlic, minced
  • 1 tbsp dried oregano
  • 1 tbsp dried basil
  • Kosher salt and ground black pepper
  • 1 can tomato paste


    1. Preheat oven to 425 degrees. Remove any stems or leaves from the tomatoes (the stick part) and arrange, stem side down in a 9x13-inch glass pan.
    2. Slide the pan into the oven and roast for 1 hour without disturbing. Remove from the oven and let cool for 30 minutes.
    3. Transfer to a covered bowl and chill overnight. Include any juices from the pan.
    4. Run the tomatoes through a food mill to remove the seeds and skins. Include any juices from the container they were in.
    5. In a large pot, heat the olive oil over medium heat. Add the onions and cook, stirring frequently, until translucent and beginning to brown (about 10 minutes). Add the garlic and cook until fragrant (about 1 minute). 
    6. Pour the tomatoes into the pot. Stir well. Add the oregano, basil, 1 teaspoon of salt and 1/2 teaspoon of pepper. Stir well.
    7. Reduce the heat to its lowest setting. Cover and simmer the sauce for 30 minutes. Add the tomato paste and stir thoroughly to combine. Cover and simmer for another 30 minutes. 
    8. Remove the cover and taste. Adjust the seasonings as desired. If the sauce seems acidic, stir in 1/4 to 1/2 teaspoon of baking soda. Use this sparingly though.
    9. Use the sauce immediately or store it in the fridge for up to five days. It can also be frozen.


Tuesday 31st of December 2019

Hi Sarah,

For the acidity, do I use baking powder or baking soda? In the article it says “powder” and in the recipe instructions it says “soda”. I don’t want to ruin this delicious sounding sauce!

Thank you and Happy 2020!

Sarah Walker Caron

Tuesday 31st of December 2019

Hi Irene! So sorry for the typo in the text. The recipe is correct: use baking soda for the acidity. Thank you and happy new year! — Sarah


Friday 13th of September 2019

I'm a glass jar hoarder too!


Thursday 12th of September 2019

I am beyond envious of your tomatoes. Growing tomatoes in Colorado is never easy because our nights always get cool but this past season we had a cool and wet June so I didn't even get them planted until July which has resulted in a pathetic harvest.

I have some out there now though and I'm really tempted to make it into your sauce, it sounds divine.

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