Preheat your oven to 350F
Pour 1 cup of broth into the bottom of an oven-safe dish. Add in chicken breasts and sprinkle salt and pepper, to taste. Cover with lid or foil and place in a preheated oven for about 30 minutes or until the chicken is cooked through (165F internal temperature if using a meat thermometer).
While the chicken is cooking, dice your onion, celery, and carrots and set aside
Once your chicken is cooked, take it out of the oven to cool.
In a large pot or Dutch oven, heat olive oil or avocado oil and add diced vegetables.
Once veggies are cooked down for about 5 minutes, add in flour and mix well.
Pour broth into pot and stir well, ensuring all the flour has dissolved into the broth.
Once the cooked chicken is cool enough to handle, shred it either by hand or using a stand mixer.
Add your shredded chicken to the soup.
Add in uncooked orzo and mix well. The orzo takes about 10 minutes to cook through.
Add freshly squeezed lemon juice to the soup pot and combine well. Serve immediately.