Preheat and prep: Heat your oven to 375°F (190°C). Grease a 9x13-inch casserole dish. Pat the chicken dry and slice into thin strips or small bite-size pieces for faster cooking.

Season the chicken: Toss the chicken with 1 teaspoon salt, 1/2 teaspoon black pepper, 1 teaspoon smoked paprika, and 1/2 teaspoon garlic powder.

Sear the chicken: Heat 1–2 tablespoons oil in a large skillet over medium-high heat. Add chicken in a single layer and sear until browned and just cooked through, 5–7 minutes total. Work in batches to avoid steaming. Transfer to a bowl.

Sauté the veggies: In the same pan, add another splash of oil if needed. Add sliced peppers, onions, and mushrooms. Season with a pinch of salt and pepper. Cook, stirring occasionally, until softened and lightly caramelized, about 8–10 minutes. Add minced garlic in the last minute until fragrant.

Make the creamy base: Lower heat to medium-low. Add cream cheese to the vegetables and stir until mostly melted. Pour in chicken broth, heavy cream, and Worcestershire sauce. Simmer 1–2 minutes, stirring, until smooth and slightly thickened. Taste and adjust salt and pepper.

Combine in the dish: Add the cooked chicken to the skillet and fold together, coating everything in the sauce. Transfer the mixture to the prepared casserole dish and spread evenly.

Add the cheese: Layer provolone slices over the top, slightly overlapping, or sprinkle shredded provolone evenly. For extra richness, tuck a few pieces into the mixture, not just on top.

Bake: Place the casserole on the center rack and bake 15–20 minutes, until the cheese is fully melted and the edges are bubbling.

Broil for color (optional): Switch to broil for 1–2 minutes to brown the cheese lightly. Watch closely to avoid burning.

Rest and serve: Let the casserole sit 5–10 minutes to set. Sprinkle with chopped parsley or red pepper flakes if you like. Serve as-is, or spoon into toasted hoagie rolls, over rice, or over cauliflower rice.