Prep the chicken: Pat the chicken dry and season with salt, pepper, paprika, and Italian seasoning. This helps the pieces brown well and taste like something straight from a restaurant.
Heat the pan: Warm a large skillet over medium-high heat.
Add the oil. When it shimmers, add the chicken in a single layer. Don’t crowd the pan.
Sear the chicken: Cook 4–6 minutes, turning once, until golden and just cooked through.
Transfer to a plate and keep warm. Leave any browned bits in the pan—those are flavor.
Sauté aromatics: Lower heat to medium. Add butter, then onion (if using).
Cook 2–3 minutes until softened. Stir in the garlic for 30 seconds until fragrant.
Steam-sauté the broccoli: Add broccoli and the chicken broth. Cover and cook 3–5 minutes until the broccoli turns bright green and tender-crisp.
If using frozen broccoli, cook an extra minute to evaporate excess moisture.
Make it creamy: Reduce heat to medium-low. Stir in the heavy cream and Parmesan. Let it gently simmer 1–2 minutes to thicken slightly, stirring so the cheese melts smoothly.
Bring it together: Return the chicken and any juices to the skillet.
Toss to coat everything in the sauce. Squeeze in lemon juice and add red pepper flakes if you like a kick.
Taste and adjust: Add a pinch more salt or pepper if needed. If the sauce is too thick, splash in a bit more broth or cream.
If it’s too thin, simmer another minute.
Finish and serve: Sprinkle with chopped parsley or chives. Serve straight from the skillet while it’s hot and glossy.