1/4cupfreshly squeezed lemon juiceabout 1 medium lemon
2tablespoonschopped fresh dill
In a large Dutch oven, heat the oil over medium heat. Add the carrot, celery, onion, basil, salt, pepper. Let cook until the vegetables soften and are beginning to brown, about 8 minutes (don’t rush this step; it builds important flavor).
Add the garlic and cook, stirring constantly, until fragrant, about 30 seconds.
Sprinkle the flour over the top and stir until it disappears. Pour in 6 cups of the chicken broth and stir to combine. The flour should be completely dissolved.
Carefully lower the chicken into the broth. Bring the soup to a boil, then reduce the heat, partially cover the pot, and let gently simmer for 10 to 15 minutes, until the chicken is cooked through and reaches 165 degrees F on an instant read thermometer. Check the soup periodically to make sure you are maintaining a gentle simmer vs. a rapid boil.
Remove the chicken to a cutting board and cover. Let rest at least 5 minutes.
Return the soup to a simmer, then stir in the orzo. Continue to simmer for 7 additional minutes, stirring periodically to keep the orzo from sticking, until the orzo is very al dente (it should be nearing done but still be too firm to eat).
Dice or shred the chicken, then add it to the pot.
Stir in the spinach, lemon juice, and dill. If you desire a thinner soup, add the remaining 1 to 2 cups chicken broth, until the soup is to your liking. Continue to simmer and stir periodically for 3 to 5 additional minutes, until the spinach wilts and the orzo is al dente. Taste and add additional salt and pepper as desired. Enjoy warm.
*You can also make this soup with another small pasta, such as small shells, castellane, or ditalini; reference the cooking time on the box and adjust your cooking time in the recipe as needed.
TO STORE: Refrigerate soup in an airtight storage container for up to 4 days.
TO REHEAT: Rewarm leftovers in a Dutch oven on the stovetop over medium-low heat or in the microwave.
TO FREEZE: Orzo soup can be frozen. Freeze soup in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.
TO MAKE IN A SLOW COOKER: Lightly coat a 5- to 6-quart slow cooker with cooking spray. Place the chicken in the bottom, then season with salt and pepper. Add the carrots, celery, onion, garlic, and basil. Pour the chicken broth over the top. Cover and cook until the chicken is cooked through, about 1 hour 45 minutes to 2 hours 30 minutes on HIGH or 4 to 6 hours on LOW. Remove the chicken from the slow cooker and shred or chop, then return to the slow cooker along with the orzo. Turn the heat to high and let cook, uncovered, for 30 minutes. Add the spinach, lemon juice, and dill. Cover and continue cooking on high for 5 additional minutes, just until the spinach wilts. Taste and add additional salt and pepper as desired.