Prep the oven and pan: Preheat oven to 375°F (190°C). Lightly oil a 9x13-inch baking dish or similar casserole.
Season the chicken: Pat chicken dry. Season both sides with 1 teaspoon salt, 1/2 teaspoon black pepper, 1/2 teaspoon paprika, and 1/2 teaspoon onion powder.
Drizzle with oil and rub to coat.
Optional quick sear: For extra flavor, sear the chicken in a hot skillet (2–3 minutes per side) just to get light color. Not required, but it adds depth.
Make the cream cheese mixture: In a bowl, mix softened cream cheese, mayonnaise, heavy cream, Parmesan, garlic, remaining paprika and onion powder, Italian seasoning, lemon juice, and a pinch of salt and pepper. Stir until smooth.
Assemble: Arrange chicken in the baking dish in a single layer.
Spread the cream cheese mixture evenly over the top. Sprinkle shredded cheese over everything.
Bake: Bake uncovered for 25–35 minutes, until the chicken reaches 165°F (74°C) in the thickest part and the top is bubbling and lightly golden.
Broil for color (optional): Turn the broiler on high for 1–2 minutes to get a deeper golden top. Watch closely to avoid burning.
Rest and garnish: Let it rest 5 minutes so the sauce settles.
Garnish with chopped parsley or chives.
Serve: Spoon chicken and sauce over cauliflower rice, sautéed spinach, roasted broccoli, or zucchini noodles.