Toss the chicken thigh pieces with 1 tbsp Cajun seasoning and the shrimp with the remaining 1 tbsp Cajun seasoning in separate bowls. Rest at room temperature for 10 minutes.

Heat a cast iron skillet over medium-high heat. Add the 1 tbsp olive oil and 1 tbsp butter. Sear the chicken 5 to 6 minutes per side until it reaches 165°F (74°C) with a deep brown crust. Transfer to a plate and tent with foil.

Add 1 tbsp butter to the same pan. Cook the shrimp 1 to 2 minutes per side over medium-high heat until pink and curled into a C shape. Remove to the plate with the chicken.

Reduce heat to medium. Add the remaining 1 tbsp butter and cook the 4 cloves minced garlic for 30 seconds. Pour in the 3 tbsp bourbon, then add the 2 tbsp soy sauce, 1 tbsp brown sugar, 1 tsp smoked paprika, and 1/2 tsp cayenne. Simmer 2 to 3 minutes until the sauce thickens and coats the back of a spoon.

Return the chicken to the pan, turning each piece in the glaze. Add the shrimp back in and warm everything over medium-low heat for 1 to 2 minutes. Transfer to a serving plate or serve from the skillet, scatter over the 2 tbsp parsley, and add lemon wedges alongside.