• Heat 2 tablespoons of olive oil in a large stock pot over medium heat. If the pan is dry, add another tablespoon of oil before proceeding.
• Season chicken with salt and pepper. Cook chicken until it's no longer pink and cooked through, then remove and set aside.
  
• Add the onion, carrot, and celery to the pot. If necessary, drizzle additional olive oil over the vegetables to prevent sticking.
  
• Make a well in the center of the vegetables, then add the minced garlic and dried Italian seasoning. Cook for another minute, allowing the flavors to blend.
• Pour in the chicken stock, add the parsley, and return the cooked chicken to the pot. Mix to combine, scraping any browned bits from the bottom of the pan.
  
• Bring the soup to a boil, then cover and lower the heat to simmer for 10 to 15 minutes, or until the vegetables are tender to your liking.
• Increase the heat to medium-high, bring to a boil, and add the tortellini and spinach. Simmer until the tortellini is cooked through, about 3 to 4 minutes.
• Taste for seasoning and adjust salt and pepper as needed before serving. Optionally, top with grated Parmesan cheese.

Slow Cooker Method

• Follow the stovetop instructions up to step 2, where the garlic is added and cooked for a minute. Transfer the sautéed vegetables and garlic to the slow cooker.
• Add the chicken stock, cooked chicken, bay leaf, thyme, salt, and pepper. Stir to combine. Cover and cook on low for 6–7 hours or high for 3–4 hours, allowing the flavors to meld.
• About 30 minutes before serving, add the tortellini to the slow cooker. Cook on high until the tortellini is tender, about 20–30 minutes.
• Remove the bay leaf and adjust seasoning as needed.Serve warm, garnished with parsley or Parmesan, if desired.