Prep the dish: Lightly grease a 9x13 baking dish or your slow cooker insert.
Place the chicken in a single layer. Pat dry with paper towels.
Season: Sprinkle chicken evenly with salt, pepper, onion powder, Italian seasoning, and red pepper flakes if using.
Add flavor boosters: Scatter chopped sun-dried tomatoes and minced garlic over the chicken. Drizzle with the sun-dried tomato oil or olive oil.
Build the sauce base: Pour chicken broth and heavy cream evenly over the chicken.
Nestle the cream cheese cubes around the dish. Sprinkle Parmesan on top.
To bake: Cover tightly with foil and bake at 375°F (190°C) for 25 minutes. Uncover, stir the sauce gently to melt the cream cheese, and bake another 10–15 minutes, until the chicken reaches 165°F and the sauce is smooth and creamy.
To slow cook: Cover and cook on Low for 3–4 hours or High for 2–3 hours, until the chicken is tender.
Stir the sauce to incorporate the cream cheese fully.
Finish: Taste and adjust salt and pepper. Slice or shred the chicken if you like. Stir in a splash of cream or broth if you prefer a looser sauce.
Serve: Spoon over pasta, rice, or mashed potatoes.
Top with fresh basil or parsley.