Slow Roasted Tomato Basil Soup

Slow Roasted Tomato Soup

Slow Roasted Tomato Soup by Dietitian Erica Julson

Tomato soup MIGHT be one of my favorite foods.

I’ve made it many times, many different ways. Fresh tomato, canned tomatoes, whole tomatoes, diced tomatoes, etc. and hands down, the best results come by oven roasting whole canned san marzano tomatoes until beautifully caramelized, and using that for the base of the soup.

The roasting imparts such a deep, rich, caramelized flavor that you can’t get anywhere else, and if you are going to roast the tomatoes, it’s much easier to start with whole canned tomatoes instead of fresh. They’re already pre-cooked and peeled for you, and  you know they’re delicious because they were picked in peak-season and then canned right away. That way you can enjoy tomato soup during the winter when tomatoes are not in season, and save those in-season tomatoes for caprese salad and gazpacho 😉

It’s really easy to roast canned tomatoes. Purchase 2 large (28oz) cans of whole, peeled, san marzano tomatoes, pull them out of the juices, slice in half, and place cut side up on a baking sheet, like so:

Canned Tomatoes on a Baking Sheet for Roasting

It took about 1 1/2 large cans to fill my baking sheet.

Then you drizzle them with olive oil, season with kosher salt & pepper, toss & spread out evenly, and roast for about 30-40 minutes until nice and golden and lovely:

Roasted Canned Tomatoes

Look at that beautiful caramelization!

Oven Roasted Tomatoes

Then you just sauté some onions, (I like to add a little pinch of red pepper flakes for some spice), add some fresh or roasted garlic, tomatoes, broth, and a little butter for richness and simmer to combine the flavors. Stir in some fresh basil, some half and half or cream for richness (optional), and some vinegar for a hit of acid (my faves are balsamic or red wine vinegar). Puree to combine and enjoy right away.

And of course, don’t forget the sprinkle of parmesan cheese on top!

Rich and Creamy Slow Roasted Tomato Soup


Slow Roasted Tomato Soup

Slow Roasted Tomato Basil Soup

5 from 1 vote
Prep20 mins
Cook1 hr 30 mins
Total1 hr 50 mins
Servings: 4


  • 1 head garlic
  • 1/2 cup extra virgin olive oil
  • 1 1/2 28 oz cans whole peeled tomatoes (preferably a high-quality san marzano brand)
  • Kosher salt
  • Freshly ground black pepper
  • 2 small onions, diced
  • 1/4 teaspoon dried red pepper flakes
  • 1 quart chicken stock
  • 2 tablespoons unsalted butter
  • 1 cup fresh basil
  • 1/4 cup half and half
  • 1 tablespoon balsamic vinegar
  • Grated parmesan or romano cheese, for serving


  • Preheat the oven to 400 degrees Fahrenheit.
  • Take out a small baking dish and a large rimmed baking sheet.
  • Peel the extra layers of papery skin off of the garlic bulb until you can see the individual cloves, but leave the whole bulb intact. Cut the top off of the bulb, just enough to expose the top of each clove. Drizzle with olive oil, rub the oil all over the bulb, and wrap in aluminum foil. Place the wrapped head of garlic on the small baking dish & set aside.
  • Next, open the cans of tomatoes. Take the tomatoes out of the cans, one by one, squeezing each tomato gently and letting any extra juices drip back into the can. Cut each tomato in half, lengthwise, and place on the large rimmed baking sheet. Continue halving the tomatoes until you have filled your large baking sheet. Save any extra tomato juice and whole tomatoes for another use (perhaps a quick tomato sauce or shakshuka).
  • Drizzle the tomatoes with olive oil, and season liberally with kosher salt and freshly ground black pepper. Toss the tomatoes to coat well, and redistribute into neat rows.
  • Place the sheet of tomatoes and the small baking dish with the garlic in the oven and roast for about 40 minutes, until the tomatoes are golden and caramelized and the garlic is completely softened.
  • When the tomatoes and garlic are done, let cool for a few minutes, then use a spatula to scrape up the tomatoes and any caramelized bits from the baking sheet. Unwrap the garlic and squeeze each clove out of its skin. Set aside for later.
  • In a large soup pot, warm 2 tablespoons olive oil over medium heat until shimmering. Add the diced onions and red pepper flakes, and sauté, stirring occasionally, until the onions are softened and lightly browned.
  • Add the butter, tomatoes + their caramelized bits and any juices, roasted garlic, and chicken stock. Bring to a boil, then reduce the heat and simmer, uncovered, for 30 minutes. 
  • Turn off the heat and stir in the fresh basil, half and half, and balsamic vinegar. Use an immersion blender to blend until smooth, or transfer to a blender and blend until smooth.
  • Ladle into bowls, sprinkle with cheese, and enjoy!
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One thought on “Slow Roasted Tomato Basil Soup

  1. 5 stars
    I’m not a big fan of tomato soup but the family loves it. This recipe changed my mind. It was like a cross between a marinara sauce and tomato soup. Thanks.

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