Prep the chicken: Pat the chicken dry and cut into bite-size pieces or thin strips. Season both sides with salt, pepper, paprika, and half the Italian seasoning.
Sear for flavor: Heat olive oil in a large skillet over medium-high. Add the chicken in a single layer.
Cook 3–4 minutes per side until browned and mostly cooked through. Remove to a plate and set aside.
Build the base: Lower heat to medium. Add butter to the same skillet.
Stir in the onion and cook 2–3 minutes until soft and translucent. Add garlic and red pepper flakes; cook 30 seconds until fragrant. Scrape up browned bits as they release flavor.
Deglaze and simmer: Pour in chicken broth and bring to a gentle simmer.
Let it reduce by about one-third, 2–3 minutes. This concentrates the flavor and makes the sauce richer.
Creamy goodness: Stir in the heavy cream and remaining Italian seasoning. Simmer 2 minutes to thicken slightly.
Keep the heat at a gentle bubble, not a hard boil.
Add the cheese: Sprinkle in parmesan and stir until melted and smooth. Taste and adjust salt and pepper. The sauce should be savory and lightly garlicky.
Return the chicken: Add the seared chicken (and any juices) back to the pan.
Simmer 3–4 minutes until cooked through and the sauce coats the pieces.
Wilt the spinach: Add the spinach in batches, stirring until it wilts and folds into the sauce. This takes 1–2 minutes. Don’t overcook; you want it vibrant and tender.
Finish with brightness: Stir in lemon juice.
This small step balances the creamy sauce and keeps the dish lively.
Serve: Top with extra parmesan and chopped parsley. Enjoy as-is, or pair with cauliflower rice, zoodles, or sautéed zucchini for a complete keto meal.