01 - Heat a large, deep skillet or Dutch oven over medium-high heat. Add butter and let it melt completely.
02 - Toss the diced chicken with 1 tablespoon of Cajun seasoning, salt, and pepper. Add chicken to the pan and sauté until browned on all sides, approximately 4-5 minutes. Remove chicken and set aside.
03 - In the same pan, add chopped onion and red bell pepper. Sauté for 3 minutes until softened, then add garlic and cook for another 30 seconds until fragrant.
04 - Add orzo to the pan, stirring constantly to coat in the flavors for about 1 minute until lightly toasted.
05 - Pour in chicken broth and heavy cream, scraping up any browned bits from the bottom of the pan. Stir in the remaining Cajun seasoning and smoked paprika until well combined.
06 - Return the chicken to the pan. Bring to a gentle simmer, reduce heat to low, cover, and cook for 12-15 minutes, stirring occasionally, until orzo is al dente and liquid is mostly absorbed.
07 - Stir in Parmesan cheese, spinach (if using), and crushed red pepper flakes if desired. Cook for 1-2 more minutes, until cheese is melted and spinach is wilted.
08 - Taste and adjust salt and pepper as needed. Remove from heat and let rest for a couple of minutes to allow flavors to meld before serving.
09 - Sprinkle with chopped fresh parsley and serve immediately while hot.