Season the chicken: In a small bowl, mix salt, pepper, Italian seasoning, and garlic powder. Sprinkle evenly on both sides of the chicken.
Sear the chicken: Heat olive oil in a large, deep skillet over medium-high.
Add chicken in a single layer. Cook 4–5 minutes per side until golden. Transfer to a plate.
It doesn’t have to be cooked through yet.
Build the flavor base: Lower heat to medium. Add minced garlic and sun-dried tomatoes to the skillet. Sauté 30–60 seconds until fragrant, scraping up browned bits.
Deglaze and simmer: Pour in chicken broth.
Bring to a gentle simmer for 2–3 minutes to reduce slightly.
Melt the cream cheese: Stir in cream cheese cubes, letting them melt into the broth. Whisk or stir until smooth and creamy.
Finish the sauce: Add half-and-half (or cream) and Parmesan. Stir until well combined.
Taste and season with a pinch of salt and pepper if needed.
Return the chicken: Nestle the chicken and any juices back into the pan. Reduce heat to low. Simmer 5–8 minutes, or until the chicken is cooked through and the sauce slightly thickens.
Add greens and brightness: Stir in spinach until just wilted.
Squeeze in lemon juice if using, and add a pinch of red pepper flakes for heat.
Garnish and serve: Top with chopped basil or parsley and extra Parmesan. Serve hot over pasta, rice, or with crusty bread.