Prepare the chicken so you have about 3 cups of cooked chicken to add to the soup.

Heat the butter and olive oil over medium-high heat.

Add the mirepoix mixture and cook until it is starting to soften and brown a bit, about 5 - 7 minutes.

Add the seasonings, Italian herbs, garlic powder, harissa, red pepper flakes, salt and pepper and cook until fragrant, stirring often, for about 1 - 2 minutes.

Stir in the frozen spinach and cook until it starts to soften, about 2 minutes more.

Drain the petite diced tomatoes, green beans, carrots and white beans.

Add all the drained vegetables and the beans, the can of crushed tomatoes, the chicken and the chicken broth to the soup pot.

Stir until well combined and beginning to simmer. Simmer for at least 15 minutes to allow flavors to meld.