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There’s something especially satisfying about making tomato soup when fresh tomatoes are at their best. Once the tomatoes and garlic start roasting, the kitchen fills with that warm, savory smell, and by the time the onions are golden and caramelized, you already know you’re headed toward a really good bowl of soup.
This roasted tomato basil soup is simple, fresh, and full of tomato flavor. Roasting the tomatoes brings out their natural sweetness, caramelized onions give the soup extra depth, and fresh basil brightens everything up at the end. I love it piping hot with a grilled cheese sandwich or a thick slice of crusty bread for dipping.
It’s also a wonderful recipe when you have a pile of ripe garden tomatoes to use. Make it thick and tomato-forward, or stir in one of the optional creamy additions when you’re craving something a little richer.
Why You’ll Love This Recipe
The tomatoes are roasted first. Instead of going straight into the soup pot, the tomatoes roast with garlic for 40-45 minutes. That extra step concentrates their flavor and gives the finished soup a wonderful roasted quality.
Caramelized onions make it extra flavorful. Slowly cooking the onions until golden brings out their natural sweetness and adds another layer of flavor to the tomatoes.
You only need a handful of simple ingredients. Fresh tomatoes, garlic, onions, basil, oregano, olive oil, and broth make up the base. Nothing complicated is needed to make the soup taste satisfying.
You decide how creamy it is. Leave it as is for a lighter tomato soup, or add coconut milk, whole milk, heavy cream, Parmesan, or butter using the options included in the recipe.
It’s made for tomato season. If your garden or farmers market haul has left you with more ripe tomatoes than you know what to do with, this recipe puts 3 pounds of them to very good use.
Roasted Tomato Basil Soup Ingredients
You only need a handful of fresh, simple ingredients to make this roasted tomato basil soup. Here’s what each one brings to the recipe:
For the Roasted Tomatoes
- Roma or Plum Tomatoes – These are the heart of the soup. Roasting them concentrates their tomato flavor and brings out their natural sweetness.
- Garlic – Roasting the garlic alongside the tomatoes softens its sharpness and gives the soup a deeper, savory flavor.
- Olive Oil – Helps the tomatoes and garlic roast beautifully while adding a little richness.
- Salt and Pepper – Simple seasonings that bring out the flavor of the roasted tomatoes and garlic.
For the Caramelized Onions
- Yellow Onions – Slowly cooking the onions until golden brings out their natural sweetness and gives the soup extra depth.
- Olive Oil – Used to cook the onions until they’re soft, golden, and caramelized.
For the Tomato Basil Soup
- Fresh Basil – Adds freshness and that classic tomato-and-basil flavor. It’s blended right into the soup with the roasted tomatoes and onions.
- Dried Oregano – A little oregano adds an earthy, herby note that works beautifully with the tomatoes and basil.
- Water or Vegetarian Broth – This thins the blended tomatoes to your preferred consistency. Use less for a thick soup or more for a lighter one.
- Salt and Pepper – Add these to taste at the end to bring all of the flavors together.
Optional Add-Ins
- Coconut Milk – A great option when you want a creamier soup while keeping it vegan.
- Whole Milk or Heavy Cream – Adds richness and gives the tomato soup a smoother, creamier texture.
- Parmesan Cheese – Adds a salty, tangy finish that pairs especially well with tomatoes and basil.
- Butter – A tablespoon or two gives the finished soup an extra-rich, silky flavor.
Step-by-Step Instructions
Roast the tomatoes and garlic
Start by heating the oven to 400 degrees F and lining a large baking sheet with parchment paper. Arrange the halved tomatoes and garlic on the pan, drizzle everything with the olive oil, and season generously with salt and pepper.
Roast for 40-45 minutes. During this time, the tomatoes will soften and their flavor will become more concentrated, while the garlic roasts right alongside them.
Caramelize the onions
While the oven does its work, turn your attention to the onions. Add the olive oil to a large pot over medium heat, then add the thinly sliced onions and stir to coat them.
Let them cook slowly, stirring occasionally and checking every 5-10 minutes. After about 20 minutes, they should be completely caramelized and golden. This is one step worth giving a little patience—the onions bring a lovely sweetness to the finished soup.
Blend until smooth
Let the roasted tomatoes and garlic cool for 10 minutes before transferring them to a food processor or high-powered blender. Blend until smooth, then add the fresh basil and caramelized onions and blend again.
If you have an immersion blender, you can also put everything directly into the large pot and blend it there.
Simmer the soup
Transfer the blended mixture back to the pot and set it over medium-low heat. Add the oregano, vegetarian broth, salt, and pepper.
Use the amount of broth in the recipe to make the soup as thick or thin as you like. This is also the time to add any of the optional creamy additions.
Let everything simmer together for 10 minutes. Spoon the soup into bowls and, if you’d like, finish it with Parmesan and serve it with grilled cheese.
Expert Tips
Start with good tomatoes. This is a tomato-forward recipe, so ripe, flavorful Roma or plum tomatoes will give you the best result.
Don’t rush the onions. You want them golden and caramelized rather than simply softened. That slow cooking is what develops the sweetness that works so well with the roasted tomatoes.
Adjust the broth gradually. If you love a thick, velvety tomato soup, begin with less broth. Add more until the consistency is just right for you.
Season at the end, too. The sweetness and acidity of fresh tomatoes can vary, so taste the soup after it has simmered and adjust the salt and pepper as needed.
For an extra-smooth bowl, strain it. There’s no need to remove the tomato seeds, but you can pass the finished soup through a fine-mesh strainer if you prefer a smoother texture.
Recipe Variations
One of the nice things about this soup is that the simple tomato and basil base leaves room to choose the finish you’re craving.
For a creamy vegan tomato soup, add the light or regular coconut milk listed in the recipe.
For a classic creamy version, use whole dairy milk or heavy cream.
For something a little more savory, add Parmesan cheese. Its salty, tangy flavor pairs naturally with the tomatoes and basil.
And when you want an especially rich bowl, stir in a tablespoon or two of butter.
You can also change the texture without adding anything extra. Use closer to 1 cup of the water or vegetarian broth for a thicker soup, or move toward 2 cups for a lighter consistency.
Storage & Reheating
This is a good soup to make ahead because the leftovers keep well.
Store the cooled soup in an airtight container in the refrigerator for up to 4-5 days. When you’re ready for another bowl, warm it gently on the stovetop or reheat it in the microwave.
You can also freeze the soup for up to 3 months in a freezer-friendly airtight container. Let it thaw in the refrigerator before reheating it on the stovetop or in the microwave.
Serving Suggestions
For me, tomato soup practically asks for something crisp and cheesy alongside it. A hot grilled cheese sandwich is the obvious choice, especially when you can tear off a corner and dip it straight into the soup.
Crusty bread is just as good when you want to keep things simple. Try sourdough, toasted country bread, garlic bread, or focaccia—anything sturdy enough to soak up the tomato soup without falling apart immediately.
If you want to turn it into a fuller meal, add a simple green salad or roasted vegetables on the side. And for serving, a little Parmesan over the top makes an easy finishing touch.
However you serve it, this is the kind of soup that’s especially good when it’s steaming hot, the bread is within reach, and fresh tomatoes are still in season.
Recipe FAQs
1. Do I need to peel or remove the seeds from the tomatoes?
No, you do not need to peel or seed the tomatoes before roasting. Simply cut them in half and roast as directed. If you prefer an extra smooth tomato soup, you can strain it through a fine mesh strainer after blending.
2. How can I make the soup thicker or thinner?
Start with less broth if you like a thicker tomato soup. The recipe calls for 1-2 cups water or vegetarian broth, so you can slowly add more until it reaches the consistency you like.
3. Can I make this tomato basil soup creamy?
Yes! For a creamy vegan soup, add light or regular coconut milk. You can also use whole milk or heavy cream for a creamy texture. A tablespoon or two of butter is another easy way to make the soup taste richer.
4. Can I use an immersion blender instead of a regular blender?
Yes, an immersion blender works great and makes cleanup easier too. Simply add the roasted tomatoes and remaining ingredients to the large pot and blend until smooth. A food processor or high-powered blender will work as well.
5. What if my tomato soup is too thick after storing it?
Simply add a little water or vegetarian broth while reheating. Stir in a small amount at a time until the soup reaches your desired consistency, then heat until warmed through.
Roasted Tomato and Basil Soup
Ingredients
Roasted Tomatoes
- 3 pound roma or plum tomatoes, cut in half
- 3 cloves garlic, peeled
- 3 tbsp olive oil
- Freshly ground salt and pepper
Caramelized Onions
- 1/2 tbsp olive oil
- 2 yellow onions, thinly sliced
For the Soup
- 1/2 cup packed basil leaves
- 1/2 tsp dried oregano
- 1-2 cups water or vegetarian broth, depending on how thick you want the soup
- Freshly ground salt and pepper, to taste
Optional Add-Ins
- Light/Regular coconut milk for a creamy vegan soup
- Whole dairy milk/heavy cream for a creamy texture
- A tablespoon or two of butter, for richer flavor
- Parmesan cheese, for a tangy, flavor enhancing flavor
Instructions
- Heat the oven to 400 degrees F and line a large baking sheet with parchment paper. Arrange the halved tomatoes and peeled garlic cloves on the prepared sheet. Drizzle them with 3 tablespoons of olive oil, then season generously with salt and pepper. Roast for 40-45 minutes.
- While the tomatoes cook, prepare the onions. Pour 1/2 tablespoon olive oil into a large pot and set it over medium heat. Add the sliced onions and stir so they are coated with the oil. Continue cooking, stirring from time to time. Check them every 5-10 minutes and cook until the onions are fully caramelized and golden. This usually takes 20 minutes.
- When the tomatoes and garlic have finished roasting, let them cool for 10 minutes. Transfer them to a food processor or high-powered blender and blend until smooth. Add the basil and caramelized onions, then blend again. As another option, place the roasted tomatoes directly into the large pot and blend everything with an immersion blender.
- Return the blended soup to the pot if needed and place it over medium-low heat. Stir in the oregano, vegetarian broth, and salt and pepper to taste. Add any of the optional ingredients listed above if desired. Simmer the soup for 10 minutes before serving.
- If desired, finish each serving with Parmesan cheese and pair the soup with grilled cheese. Serves 4.
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Recipe Notes
- The tomato seeds do not need to be removed. For a smoother result, however, the soup can be passed through a fine-mesh strainer.
- Place leftover soup in an airtight container and refrigerate for up to 4-5 days. Reheat on the stovetop or in the microwave.
- Transfer leftover soup to a freezer-safe airtight container and freeze for up to 3 months. Thaw it in the refrigerator before reheating on the stovetop or in the microwave.
Nutrition
Calories: 214kcal | Carbohydrates: 21g | Protein: 3g | Fat: 14g | Saturated Fat: 2g | Fiber: 3g | Sugar: 9g Nutrition is per serving, based on 4 servings, and does not include optional add-ins.
