Preheat oven to 375 degrees F and line a baking sheet with parchment paper.
In a small bowl, mix together all the ingredients for the cajun seasoning. Set aside.
Place chicken breasts on a lined baking sheet and evenly sprinkle ½ of the Cajun seasoning over them, flip and add remaining seasonings to the other side.
Bake in preheated oven for 20 minutes or until the internal temperature reaches 165 degrees F.
While chicken is baking, heat 1 tablespoon of oil in a large cast iron skillet over medium-high heat and add shrimp. Sprinkle with ½ of the Cajun seasoning and cook about 3-4 minutes or until shrimp are pink and cooked through; remove and set aside.
Add remaining oil to skillet along with garlic and ½ of the butter. Sauté for 1-2 minutes, stirring often.
Add chicken bone broth, mushrooms, onions, and dried parsley; stir to combine and bring mixture to a simmer. Simmer for 3-4 minutes or until mushrooms are tender. Reduce heat to low and add remaining butter, stirring until melted completely into sauce.
Add cooked chicken breasts back into the skillet along with shrimp; stir everything together to coat in sauce before adding fresh parsley over the top as garnish.