Prep the chicken: Pat the chicken dry.
Season both sides with salt, pepper, garlic powder, and Italian seasoning. If the breasts are thick, slice them horizontally to make cutlets for quicker, more even cooking.
Sear for flavor: Heat olive oil and butter in a large skillet over medium-high heat. Add the chicken and sear 4–5 minutes per side until golden and nearly cooked through.
Transfer to a plate and tent with foil.
Sauté aromatics: Lower heat to medium. Add minced garlic to the pan and cook 30 seconds until fragrant, scraping up browned bits. If the pan looks dry, add a splash of oil or butter.
Build the sauce base: Pour in the chicken broth and simmer 2 minutes to reduce slightly.
Stir in heavy cream and bring to a gentle simmer.
Add flavor boosters: Stir in Parmesan, sun-dried tomatoes, and red pepper flakes if using. Simmer 2–3 minutes until the sauce lightly thickens.
Wilt the greens: Add the spinach and stir until just wilted. Taste and adjust seasoning with salt and pepper.
For brightness, add a squeeze of lemon juice.
Finish the chicken: Return the chicken and its juices to the pan. Spoon sauce over the top and simmer 3–5 minutes, or until the chicken reaches 165°F internally and the sauce is creamy.
Garnish and serve: Sprinkle with fresh basil or parsley. Serve hot over cauliflower rice, zucchini noodles, sautéed green beans, or a simple salad.