Season the chicken: Pat the chicken dry. Sprinkle with salt, pepper, garlic powder, and paprika on both sides.
Sear: Heat olive oil in a large skillet over medium-high.
Add chicken and cook until golden and cooked through (internal temp 165°F), about 4–5 minutes per side for thin breasts. Transfer to a plate and tent with foil.
Make the base: Reduce heat to medium. Add butter to the same skillet.
Stir in minced garlic and cook 30–60 seconds until fragrant, scraping up browned bits.
Build the sauce: Pour in chicken broth and simmer 1–2 minutes to reduce slightly. Stir in heavy cream, Italian seasoning, and red pepper flakes if using.
Thicken: Simmer gently 2–3 minutes, then whisk in Parmesan a handful at a time until melted and smooth. Add lemon juice if using.
Taste and adjust salt and pepper.
Combine: Return chicken and any juices to the pan. Spoon sauce over the chicken and simmer 2 minutes to warm through.
Finish: Garnish with chopped parsley. Serve with sautéed spinach, roasted broccoli, zucchini noodles, or cauliflower rice.