Preheat the oven: Set your oven to 375°F (190°C). Lightly grease a 9x13 baking dish if you’re not using an oven-safe skillet.
Cook the bacon: In a large skillet over medium heat, cook chopped bacon until crisp.
Transfer bacon to a paper towel–lined plate. Leave 1–2 tablespoons of bacon fat in the pan.
Season the chicken: Pat chicken dry and season both sides with salt, pepper, onion powder, Italian seasoning, and smoked paprika.
Sear the chicken: In the bacon fat (add a splash of oil if needed), sear chicken 2–3 minutes per side until golden. It doesn’t need to be cooked through yet.
Transfer to a plate.
Sauté the aromatics: Lower heat to medium-low. Add minced garlic and stir 30–60 seconds until fragrant. If using mushrooms, sauté them now until they release moisture.
Build the cream sauce: Pour in chicken broth and scrape any browned bits.
Stir in heavy cream and cream cheese. Whisk until smooth and slightly thickened, 2–3 minutes. Season with a pinch of salt and pepper.
If you like heat, add red pepper flakes.
Wilt the spinach: Add chopped spinach in batches, stirring until it softens. It will look like a lot at first but cooks down quickly.
Add cheese and bacon: Stir in half the shredded cheese and half the cooked bacon until just melted into the sauce.
Combine and top: Nestle the seared chicken into the creamy spinach mixture. Spoon sauce over the top.
Sprinkle with the remaining cheese and bacon.
Bake: Transfer the skillet to the oven (or pour into your prepared baking dish). Bake 15–20 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the top is bubbly and lightly golden.
Rest and serve: Let it rest 5 minutes so the sauce settles. Taste and finish with a crack of black pepper or a squeeze of lemon to brighten the richness.