Food / Main Dishes / Soups, Stews + Chili / Vegetarian

Classic Tomato Soup + Pesto Grilled Cheese Croutons

Classic tomato soup; is there anything better?

When it came to throwing a pot of this good stuff together, I found myself torn. Tomato basil soup is trending, and throwing roasted red peppers into the mix puts a nice spin on things—but why mess with a classic when your heart is pining for the thick and creamy tomato-y goodness you mowed down as a child?

I just couldn’t deny my heart a plain n’ simple tomato soup.

The soup stands on its own. The pesto grilled cheese croutons were included to scratch my creative itch since I kept things really simple with the soup; the pesto grilled cheese croutons are optional.

(Are they, though?)

Classic Tomato Soup | Killing Thyme

Keeping it simple.

I used canned tomatoes in this recipe and I have zero shame. Sure, a lot of recipes out there call for fresh, but hi, it’s December. So I went for canned and won anyway. I added a rib of celery—because celery belongs in almost every soup—an onion, and smashed garlic cloves.


Classic Tomato Soup | Killing Thyme

I usually substitute heavy cream with plain Greek yogurt in my creamy soups, but I stuck with the cream in this case. If you opt for plain Greek yogurt instead, please let me know how it turns out! I imagine it would be just as scrumptious.

Classic Tomato Soup | Killing Thyme

Kick the acidity with science.

When I was trying to perfect my homemade tomato sauce a few years ago, I had a hard time cutting the acidity. (I like my sauce on the smoother side.) I can’t tell you how many people told me to use sugar, but it never worked for me.

Lo and behold, baking soda gets the job done—baking soda neutralizes acidity. Drop a bit of baking soda into your sauce, give it a stir, and watch it foam and fizzle like magic science!

Despite the advice of a certain celebrated ranch-dwelling diva who calls for six tablespoons of sugar in her tomato soup (SIX TABLESPOONS!!), I stuck to my trusty baking soda in this recipe and ended up with velvety smooth perfection.

If you make this recipe, please snap a pic and tag me on Instagram @killing__thyme! I love hearing from you <3

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5 from 4 votes

Classic Tomato Soup + Pesto Grilled Cheese Croutons

This Classic Tomato Soup is rich, creamy, and reminiscent of the good ol' tomato soup we grew up on, but with wholesome ingredients!
Course Entree or Side, Lunch, Soup
Cuisine Comfort Food
Prep Time 10 minutes
Cook Time 20 minutes
Total Time 30 minutes
Servings 6
Author Killing Thyme


Classic Tomato Soup

  • 2 TBSP Butter
  • 1 medium onion, finely chopped
  • 1 rib of celery, finely chopped
  • 3 garlic cloves, smashed
  • 3 14 oz cans of diced or crushed tomatoes, including juice
  • 1 cup vegetable broth
  • 2/3 cups heavy cream
  • 2-3 tsp sugar, to taste
  • 1/4 tsp dried oregano
  • 1/2 tsp kosher salt, more to taste if needed
  • Cracked black pepper, to taste
  • 1/4 tsp baking soda, to cut acidity

Pesto Grilled Cheese Croutons (based on two servings)

  • 2 slices bread, each buttered on one side
  • 2 TBSP pesto
  • mozzarella cheese however much of it you want!


Classic Tomato Soup

  • In a stock pot or Dutch oven, melt the butter. Add the onion, celery, and smashed garlic. Simmer over moderate heat, stirring occasionally, until the onions are translucent—about 5 minutes.
  • Add the tomatoes as well as their juices, vegetable broth, heavy cream, sugar, oregano, salt, and pepper. Bring the soup to a rolling boil over high heat and break up the tomatoes with a spoon or spatula. Reduce the heat to medium-low and simmer for 10 minutes.
  • Carefully transfer the soup mixture to a powerful blender or food processor (you'll have to do this in batches), and blend until velvety smooth. Once all the soup is smooth, return it to its original stock pot. Taste and adjust seasoning. If you find the soup on the acidic side, bring it to a simmer, add the baking soda, and wait for it to foam and fizzle. Stir it, and let it simmer for about five minutes. Taste. You should have a smoother and much less acidic flavor now.

Pesto Grilled Cheese Croutons

  • Heat a cast iron or non-stick pan over moderate heat.
  • Slather one of the unbuttered sides of bread with pesto. Pile on the mozzarella, and close the sandwich with the other slice of bread, buttered side up. Carefully place on the heated pan and cook for 2-3 minutes, or until golden brown. Carefully flip, and again cook for 2-3 minutes or until golden brown and cheese has melted.
  • Remove from the pan and set on a cutting board. Allow it to cool for a few moments. Once cooled enough to handle, carefully cut the sandwich into cubes.
  • Spoon the soup into bowls, and garnish each bowl with the grilled cheese croutons.


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  • Susan
    March 16, 2018 at 12:10 pm

    5 stars
    The perfect spring/fall comfort food! Thanks for sharing ?❤️?

  • Leanne | Crumb Top Baking
    March 16, 2018 at 12:08 pm

    5 stars
    Tomato soup definitely takes me back to my childhood! And I love how you kept it simple. But I’m absolutely drooling over those croutons! They are on my must-try list for sure!

  • Nathalie
    March 16, 2018 at 10:17 am

    Soups are the essence of comfort food! It looks so delicious!

  • Elaine
    March 16, 2018 at 9:47 am

    5 stars
    A classic meal from just about everyone’s childhood–tomato soup and grilled cheese sandwiches. Love your twist on this! A smooth and creamy soup with perfectly balanced flavours! Thanks!

  • Emma
    December 29, 2017 at 5:29 pm

    5 stars
    You are my new soup queen. I’ve made about three of your soups from this blog and I can’t get over how delicious and easy they are. THANK YOU!!


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