Prep the chicken: Pat the chicken dry. Season both sides with salt and pepper. If the breasts are very thick, slice them horizontally to create thinner cutlets for even cooking.
Sear to golden: Heat olive oil in a large skillet over medium-high.
Add chicken and sear 4–5 minutes per side until deeply golden. Transfer to a plate; it may not be fully cooked yet. Keep the pan on the stove.
Sauté aromatics: Lower heat to medium.
Add garlic and red pepper flakes. Stir for 30 seconds until fragrant, taking care not to burn.
Build the base: Add Italian seasoning and sun-dried tomatoes. Stir for 1 minute to bloom the herbs and coat the tomatoes in the garlicky oil.
Deglaze: Pour in chicken broth.
Scrape up any browned bits on the bottom of the pan; that’s where the flavor lives. Simmer for 2–3 minutes to reduce slightly.
Cream it up: Stir in heavy cream and Parmesan. Simmer gently for 2–4 minutes until the sauce thickens enough to coat a spoon.
Keep the heat moderate so the dairy doesn’t split.
Return the chicken: Nestle the chicken and any juices back into the sauce. Reduce heat to low and cook 4–6 more minutes, or until the chicken reaches 165°F inside. Add butter if using.
Finish and brighten: Stir in fresh basil and lemon juice.
Taste and adjust salt, pepper, or heat as needed.
Serve: Spoon sauce over the chicken. Garnish with extra basil and a sprinkle of Parmesan. Pair with sautéed greens, roasted asparagus, zucchini noodles, or cauliflower mash.