Prep the chicken: Pat the chicken dry. Season on both sides with salt, pepper, Italian seasoning, and smoked paprika.
Let it sit for 10 minutes while you gather ingredients.
Sear the chicken: Heat olive oil and 1 tablespoon butter in a large skillet over medium-high. Add the chicken and cook until golden and cooked through, about 4–5 minutes per side depending on thickness. Transfer to a plate and tent loosely with foil.
Sauté aromatics: Lower heat to medium.
Add remaining tablespoon of butter. Stir in garlic and sun-dried tomatoes. Cook 30–60 seconds until fragrant, stirring to avoid browning the garlic.
Deglaze and build the sauce: Pour in chicken broth and scrape up browned bits from the pan.
Simmer 2–3 minutes to reduce slightly. Whisk in cream, Dijon, and red pepper flakes. Let it gently bubble for 2–3 minutes.
Add cheese and greens: Reduce heat to medium-low.
Stir in Parmesan until melted and smooth. Add spinach and cook until just wilted, about 1 minute.
Brighten and season: Stir in lemon zest and a squeeze of lemon juice. Taste and adjust salt and pepper.
The sauce should be rich but balanced with a little tang.
Return chicken to the pan: Nestle chicken back into the sauce and spoon sauce over the top. Simmer 1–2 minutes to warm through and thicken slightly.
Garnish and serve: Sprinkle with fresh basil or parsley. Serve immediately over pasta, rice, mashed potatoes, or with crusty bread.