Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper.
In a large bowl, combine all of the ingredients for the meatballs. Form into balls approximately 1/2 inch in diameter. The mixture should make about 35-40 mini meatballs. Place on a baking sheet about an inch apart and bake for 20 minutes.
Meanwhile, heat oil in a large stockpot over medium heat. Add onion, carrots, celery, and thyme. Cook until fragrant and starting to soften, about 3 to 4 minutes. Add chicken broth and bring to a boil.
Add the barley and lower to a simmer for 25 minutes. Add the meatballs and cook for an additional 5 minutes. Season with salt and pepper, to taste.
Garnish with freshly grated parmesan cheese, if desired.
If you let the soup sit for a few hours, you'll notice that the barley absorbs quite a bit of broth. You may wish to add more broth to the soup, especially if consuming as leftovers. Alternatively, if cooking this soup in advance, you can cook the barley separately and add it just before serving.
If serving this recipe to little ones, I like to slice the carrots and then quarter them so that they’re smaller and easier to chew.
I generally make mini meatballs for this soup to make it more kid-friendly, however you can make the meatballs larger if preferred.
To save on prep time, make up a batch of the meatballs in advance and freeze for later. When ready to make the soup, add the frozen meatballs at the same time you add the barley to allow them to thaw.
We like to freeze this soup in these Souper Cubes for individual portions that can be easily served as a quick and easy lunch or dinner when pressed for time!