The tomato soup I make on a 100-degree day
Sometimes the craving for tomatoes hits me out of nowhere, and recently it happened to land on the evening of yet another 100+ degree day here in Austin. While this isn’t exactly most people’s idea of the perfect time for soup, it IS indeed the perfect time for roasted tomato basil soup (it’s peak tomato AND basil season!)
Not having a ton of time to fiddle with a pot on the stove (our little guy has recently learned how to open and pull out EVERYTHING in our kitchen cabinets), I threw the seeded tomatoes, an entire bulb of garlic, and the quartered onion onto the sheet pan and popped it into the oven. About 30 minutes later the tomatoes had blistered, the garlic turned buttery and soft, and the onions got those beautiful caramelized edges.
But the part I’d keep even if I had all the time in the world? That can of San Marzanos going into the blender right alongside the roasted ones, since the fresh tomatoes bring the sweetness and the char while the canned ones bring the body.
A few minutes of blending and a quick simmer later, we were sitting down to the most delicious bowl of soup, complete with sides of crusty grilled cheeses and a handful of homemade croutons of course!
Made this, and it is DELICIOUS. I did add some chopped ginger because I like more spice.
– Anne
Ingredients and Substitutions
For the exact measurements and detailed instructions, please see the recipe card below.
Roma tomatoes: Romas are meatier and less watery than a big slicing tomato, so the soup comes out concentrated instead of thin. Cutting out the core and seeds before they hit the pan is worth the extra step.
Yellow onion: Quartered and roasted right alongside the tomatoes, it goes sweet and jammy at the edges. A sweet or red onion works too if that’s what you have.
Garlic: A whole head sounds like a lot until you roast it. The cloves turn soft and buttery in the oven and lose all of that sharp raw-garlic bite, and if you have never done it before, here is how to roast garlic on its own.
Olive oil: Just enough to coat everything so it roasts instead of steams. Regular olive oil is fine here since the oven does the flavor work.
San Marzano tomatoes: These are what give the soup its body and that deep tomato flavor no matter what time of year you make it. Any canned whole peeled tomatoes will work, but San Marzanos are worth looking for.
Broth: You only need a little, which is why I reach for Better Than Bouillon base stirred into hot water instead of opening a whole carton. Vegetable base keeps this one vegetarian, and the chicken base works just as well.
Fresh basil: This is where most of the fresh flavor comes from, so don’t skimp. A full clamshell looks like a mountain on the counter and disappears completely once it’s blended.
Dried oregano and thyme: Both go straight into the blender with the canned tomatoes, so there’s no chopping and nothing to cook down. Fresh thyme works if that’s what you have, just use more of it.
How to Make Roasted Tomato Basil Soup
Prep the tomatoes.
Cut the roma tomatoes in half lengthwise, then scoop out the cores and the seeds. Romas hold less water than most tomatoes, and pulling the seeds now is what keeps the soup from going thin later.
Use a spoon, not a knife. A regular teaspoon scrapes the seed pockets clean in one pass without taking half the flesh with it.
The Sheet Pan I L❤️VE!
Your veggies will end up steaming instead of roasting if you overcrowd the pan. So my tip… use the largest sheet pan you have and spread everything out!
Roast everything on one sheet pan.
Trim about half an inch off the pointed end of the garlic head so the cloves are exposed, then add the garlic and the quartered onion to a parchment-lined sheet pan with the tomatoes cut side up. Drizzle it all with olive oil, rubbing it into the tomato flesh and the cut garlic, and sprinkle with salt.
Flip the tomatoes so they are skin side up and roast at 400°F for 30-35 minutes, until the skins blister and the garlic is soft and golden.
Trim the pointed end, not the root end. The root plate holds the cloves together, so cutting there just makes the head fall apart without exposing anything.
Peel the roasted tomatoes.
Let everything cool for about 5 minutes, then slip the skins off the tomatoes and discard them. They should come away in one piece once the tomatoes have had a minute to sit.
The skins are the whole reason this turns out silky. Roasting them skin side up loosens them so they peel off cleanly, and pulling them means you get that smooth texture without a drop of cream.
The best immersion blender!
This stick blender is a lifesaver when it comes to blending up creamy soups or even salad dressings. It’s easy to clean, gets things silky smooth, and is pretty affordable!
Blend it smooth.
Add the peeled tomatoes and the onion to a blender, squeezing the roasted garlic cloves right out of their papery skins as you go. Blend for about 30 seconds, until it is mostly smooth but still a little chunky.
Add the canned tomatoes, broth, basil, oregano, thyme, and the remaining salt and pepper, then blend for another 1-2 minutes until it is as smooth as you want it.
Simmer and serve.
Pour the soup into a large pot or Dutch oven and simmer over medium-low for 5-10 minutes, just until it is heated through. Top with extra fresh basil and serve with grilled cheese for dipping.
Oops! What did I do wrong?
My soup came out too thin. Nine times out of ten the seeds stayed in, and they hold more water than you would think. Let it simmer uncovered for another 10 minutes and it will tighten right up.
My soup is thicker than I wanted. Add broth a tablespoon at a time with the blender running until it loosens up. Blending longer also thins it out, since the texture here is controlled by blend time rather than simmer time.
Do I really have to take the skins off? If you want it silky, yes, since the skins leave flecks that never fully break down even in a high-speed blender. They slip off in seconds once the tomatoes have cooled.
Can I use all fresh tomatoes, or all canned? You can, but you lose something either way. All fresh means the flavor swings with whatever your tomatoes taste like that week, and all canned means you miss the roasted sweetness and the char.
Storage and Reheating
Fridge: Store leftovers in an airtight container for 3-5 days. The flavor actually settles and improves after a day.
Freezer: Freeze in a freezer-safe container for up to 4-6 months. There is no cream or coconut milk in this one, so it thaws without separating or turning grainy, which is not something most tomato soups can claim.
Reheating: Warm it on the stovetop over medium-low. It comes back better on the stove than it does in the microwave.
Make ahead: Roast the tomatoes, onion, and garlic up to 3 days in advance and blend when you are ready, or make the whole pot ahead and reheat.
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Roasted Tomato Basil Soup
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Equipment
Ingredients
- 2 pounds roma tomatoes
- 1 large yellow onion quartered
- 1 medium head garlic
- 2 tablespoons olive oil
- 2 teaspoons salt divided
- 1 (28-ounce) can whole San Marzano tomatoes
- ½ cup vegetable broth see note
- 1 ounce fresh basil leaves coarsely chopped
- ½ teaspoon dried oregano
- ½ teaspoon dried thyme
- ½ teaspoon black pepper
Instructions
- Preheat the oven to 400°F. Line a large baking sheet with parchment paper.
- Cut the tomatoes in half lengthwise. Remove the cores and seeds. Place cut side up on the prepared baking sheet.
- Trim ½ inch off the pointed end of the head of garlic to expose the cloves. Add the head of garlic cut side up and the quartered onion to the baking sheet. Drizzle the tomatoes, garlic, and onion with the olive oil, rubbing it into the flesh of the tomatoes and the exposed garlic cloves and tossing the onion to coat. Sprinkle with ½ teaspoon salt.
- Flip the tomatoes so they are skin side up. Bake for 30-35 minutes, or until the tomato skins begin to blister and separate from the flesh and the garlic is soft and golden.
- Let the vegetables cool for 5 minutes, then peel and discard the tomato skins. Add the tomatoes and onion to a large high-speed blender, squeezing the roasted garlic cloves out of their skins and into the blender. Blend for 30 seconds, or until mostly smooth.
- Add the canned tomatoes, broth, basil, oregano, thyme, the remaining 1 ½ teaspoons salt, and black pepper. Blend for 1-2 minutes, or until the soup reaches your desired consistency.
- Transfer the soup to a large pot or Dutch oven. Bring to a simmer over medium heat, then reduce the heat to medium-low. Cover and simmer for 5-10 minutes, or until heated through.
- Serve with additional fresh basil and grilled cheese for dipping, if desired.
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Video
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
What to Serve With Tomato Basil Soup
Grilled cheese is the obvious answer and I am not going to pretend otherwise, but the bread matters more than the cheese does. Thick slices with crisp edges hold up to dipping instead of collapsing, and a swipe of homemade garlic butter on the outside before it hits the pan is the single easiest upgrade.
If you want something with a little crunch on top instead, homemade croutons take about 7 minutes and use up whatever bread is going stale on the counter.
For something green on the side, a green bean salad is bright enough to cut through a rich bowl of tomato soup without turning dinner into a project. And if you still have tomatoes left over from the same haul, roasted cherry tomatoes use them up and go on absolutely everything.
More Blender Soup Recipes
Turns out I have a whole habit of roasting vegetables and blending them into soup. These are the other ones we keep coming back to.
very good! the best I have, ate.
Yay! So happy to hear you enjoyed the recipe, Cassandra! This soup is one of my faves, for sure. Thanks so much for taking the time to leave a comment and rating!
The soup is very simple, and has a homely taste. Love it!🙌
Yay! So happy to hear you enjoyed the recipe, Aislyn! Thanks so much for taking the time to leave a comment and rating!
This soup is delicious! Thanks for the recipe. 😀
Yay! So happy you enjoyed the recipe, Wendy! Thanks for the comment and rating! 🙂
Added a red pepper to the roast pan…..really great!
What a great idea! Sounds delicious!