Roasted Heirloom Tomato Basil Soup

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Cast iron roasted and charred, this Homemade Tomato Basil Soup uses fresh produce from the summer garden including heirloom tomatoes, garlic scapes, and yellow onions. Roasted in the oven and smoothed in the blender for ease, this will quickly become your favorite easy way to make tomato soup.

Overhead image of tomato basil soup in a white bowl topped with fresh basil and gorgonzola cheese.

Recipes that stand the test of time

You’re going to start to notice a little bit of a change around the blog. For those of you that don’t know, we have a homestead and are steadily working towards becoming off-grid and fully self-sufficient. While I don’t know as if we will ever 100% be self-sufficient (thanks to needing the internet) we can surely try.

And if we learned anything this past year, it’s the need to be self-reliant when it comes to food and well prepared for the harsh winters that Maine can bring. This winter in particular is expected to be a doozey! Which means we will need to have fresh foods that can be heated and cooked over a wood stove, fire, or grill. And it also means that I am acting quick to preserve our harvest in any form possible. Hence, this garden tomato soup.

Close up image of tomato basil soup with a spoonful lifted out.

Homemade Creamy Tomato Basil Soup – from the garden!

Many recipes you find on the web will direct you to one or two types of tomatoes for a certain result of tomato soup. However, you’ll find here that a fresh from the garden tomato is always better than store-bought. Heirloom tomatoes are popular among farmers as they are less prone to diseases many commercial tomatoes can get. However, they do have a shorter shelf life than many other varieties.

You’ll recognize an heirloom variety by their stunning, unique shape and vibrant colors ranging from deep purple to a bright yellow. Packed with natural sugars and loaded with juice, these gorgeous creations make for the perfect base of our tomato soup. And much like the tomatoes, consider this recipe a family heirloom you’ll want to pass down for generations to come.

What are Garlic Scapes and How to use them?

Ahhhhh garlic scapes! A secret love of mine. Garlic scapes are the top of the garlic plant. Thicker and more rugged than that of a scallion, the scape is the green tube style stalk that eventually flowers from the garlic bulb. When harvesting for consumption, you don’t want to wait until the flower has bloomed. You’ll cut just above the bulb and again just below the flower and use all that is in-between. The taste of the garlic scape is more mild than that of the garlic bulbs, but still bring a noticeable garlic accent to your dish. If you don’t have garlic scapes, you can substitute each scape with one clove each.

How to make Roasted Tomato Soup

If you don’t have a cast iron casserole dish as shown in the photos, you can use a skillet or a Dutch oven to achieve the same results.

Different Cast Iron

No matter the vessel, quarter your tomatoes and onions, then add the ingredients to either a cast iron skillet or a Dutch oven. Place into a 400F oven for 30 minutes until ingredients become soft and slightly charred. If using a skillet, transfer ingredients to a blender and continue as directed. If using a Dutch oven, add the remaining ingredients directly to the Dutch oven and use an immersion blender to smooth.

On the Grill or Woodstove

This will require a bit more babysitting, but on the grill use an internal thermometer that sits on the upper rack to determine the inside temperature. Reach 400F and continue as directed but using a skillet, flipping the vegetables halfway through the cooking time. On a woodstove, use any cast iron vessel with a lid (or top with aluminum foil) and continue as directed. Depending on the temperature of your woodstove, this may take longer than 30 minutes.

Ingredient Substitutions & Tips

To make this soup dairy-free or vegan, use coconut milk in place of the heavy cream.
Don’t have heirloom tomatoes on hand? Use whatever you grew or a variety of tomatoes from the store.
No garlic scapes, no problem! Use 1 garlic clove per garlic scape – about 3 in total.
Out of fresh herbs? Use 2 teaspoons dried rosemary or thyme in place of the fresh rosemary and 1/2 Tablespoon dried basil in place of the fresh basil.
Want the tomato soup flavor with less acidity? Add 1/2 teaspoon baking soda to the roasted tomatoes before blending.
Want a unique vibrant tang? Top with a balsamic reduction at the plating of your soup.

How to Store Homemade Tomato Soup

  • Refrigerator – for short term storage, store in an air-tight container in the refrigerator for up to 5 days.
  • Freezer – for up to 3 months storage, store in a Ziploc bag, vacuum saver bag, or soup safe air-tight container about 2/3 the way full giving room for the soup to expand as it freezes. Remove as much air as possible and if using the bag method, lay flat in the freezer for 24 hours until frozen and rearrange as needed for the organization of your freezer.
  • Canning – for long term storage, pressure can tomato soup (without the added dairy) for 15 minutes in pints or quarts for 15 minutes at 10-12 pounds pressure. For waterbath canning (again without the added dairy), pints and quarts require 40 minutes. Note: adjustments need to be made for altitude.
  • Reheating – whatever method you choose, reheating can be done in a pot on the stovetop or in the microwave.
Close up image of tomato basil soup with bread being dipped in and fresh basil garnished on top.

What to serve with Tomato Soup

You can’t go wrong with a classic grilled cheese or in a bread bowl, but be sure to consider these other delicious pairings.

Other Classic Comfort Foods you’ll love!

The Perfect Steak

Skillet Brownies

Ground Beef Shepard’s Pie

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Roasted Heirloom Tomato Basil Soup

Course Appetizer, Dinner, Main Course, Soup
Cuisine American
Prep Time 10 minutes
Cook Time 30 minutes
Total Time 40 minutes
Servings 5 cups
The best and freshest Tomato Soup you can get! Made with minimal effort and loaded with rich, vibrant flavors. Roasted in cast iron and blended together in a jiff!


  • cast iron casserole dish, 5 quart dutch oven, or 12 inch skillet
  • blender or immersion blender
  • Knife
  • Cutting board


  • 3 pounds heirloom tomatoes stems removed
  • 1 onion yellow or white, outer skin removed
  • 3 garlic scapes or garlic cloves
  • 3 Tablespoons olive oil
  • 1 teaspoon salt
  • 1/2 teaspoon pepper
  • 2 sprigs rosemary
  • 1/2 cup fresh basil
  • 1/4 cup heavy cream


  • Quarter tomatoes and onions and spread into the casserole dish. Drizzle with olive oil. Sprinkle with salt and pepper. Lay rosemary leaves, removed from stems, and garlic scapes on top.
  • Bake uncovered in 400F oven for 30 minutes.
  • Carefully transfer all ingredients into a blender. Add the heavy cream and fresh basil. Blend on high until contents are smooth.
  • Top with Gorgonzola cheese, croutons, or serve along side a hearty piece of bread.


Note that while the directions refer to a casserole dish, the same can be done in a cast iron skillet or Dutch oven if you do not have a cast iron casserole dish. 
Please see post for ingredient substitutions and alternative cooking methods. 


Serving: 1cup | Calories: 186kcal | Carbohydrates: 16g | Protein: 4g | Fat: 13g | Saturated Fat: 4g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 7g | Cholesterol: 16mg | Sodium: 486mg | Potassium: 696mg | Fiber: 4g | Sugar: 8g | Vitamin A: 2571IU | Vitamin C: 42mg | Calcium: 61mg | Iron: 1mg

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One Comment

  1. Debby Blom says:

    5 stars
    I’ve made this soup several times now. Such a simple healthy soup, I don’t see the need to go back to canned tomato soup again! I can’t wait until next summers growing season, as I plan to make several batches and can this soup to be used all winter long! Pair this with a grilled cheese sandwich and it’s a little piece of heaven.