Prep the chicken: Pat chicken dry and season with salt, pepper, and Italian seasoning. If you like a slightly thicker sauce, lightly coat the chicken with flour and shake off the excess.

Heat the pan: Set a large skillet over medium-high heat. Add olive oil and 1 tablespoon butter until shimmering.

Sear the chicken: Place chicken in a single layer. Cook 3–4 minutes per side until golden and just cooked through. Work in batches if needed. Transfer to a plate and tent loosely with foil.

Sauté the garlic: Reduce heat to medium. Add remaining butter. Stir in minced garlic and cook 30–60 seconds until fragrant. Don’t let it brown.

Deglaze: Pour in chicken broth, scraping up browned bits. Let it bubble for 2–3 minutes to reduce slightly.

Make it creamy: Lower the heat to medium-low. Stir in heavy cream and Parmesan until smooth. Add a pinch of red pepper flakes if using. Simmer gently 2–3 minutes to thicken.

Brighten the sauce: Add lemon zest and a squeeze of lemon juice. Taste and adjust salt and pepper. The sauce should be savory with a hint of freshness.

Wilt the spinach: Add spinach by the handful, stirring until just wilted. It will look like a lot at first but cooks down quickly.

Finish the dish: Return chicken and any juices to the skillet. Spoon sauce over the top and simmer 1–2 minutes to warm through.

Serve: Sprinkle with chopped parsley. Serve over pasta, rice, mashed potatoes, or with crusty bread to soak up the sauce.