Season the chicken: Place the cubed chicken in a large mixing bowl and season with 1 tsp Kosher salt, 1 tsp dried oregano, and ¼ tsp black pepper. Toss well until evenly coated.

Brown the chicken: Heat 2 Tbsp olive oil and 2 Tbsp unsalted butter in a large soup pot or Dutch oven over medium-high heat. Add the seasoned chicken and cook for 4-5 minutes until browned on all sides. Use a slotted spoon to transfer the cooked chicken to a plate and set aside.

Sauté aromatics: In the same pot, add 1 diced sweet onion and 2 finely chopped celery sticks. Season with ½ tsp Kosher salt and cook until soft and translucent, about 3-5 minutes. Stir in ½ cup finely chopped sun-dried tomatoes, 4 cloves finely chopped garlic, and 2 Tbsp tomato paste. Mix well to break up the paste.

Build the broth: Pour in 4 cups low-sodium chicken broth and 2 Tbsp pesto, adding the Parmesan rind if using. Bring to a gentle boil, then reduce to a simmer and cook for 10-15 minutes.

Cook the gnocchi: Return the chicken to the pot along with its juices and stir in 16 oz dried potato gnocchi. Cook for 3-5 minutes until the gnocchi float and are tender.

Finish the soup: Stir in ½ cup heavy cream, 5 oz fresh baby spinach, and ½ cup grated Parmesan cheese. The spinach will wilt quickly.

Adjust seasoning: Taste and adjust seasonings with Kosher salt and black pepper as needed before serving.