Pat chicken dry, then season both sides with salt and pepper. Heat olive oil in a large skillet over medium-high heat until it shimmers. Add chicken and sear 4–5 minutes per side, until golden and just cooked through. Transfer to a plate and tent with foil (it’ll rest while you make sauce).

Reduce heat to medium. Add minced garlic to the same pan—no extra oil needed. Stir constantly for 30 seconds, until fragrant but not browned (burnt garlic tastes bitter).

Pour in chicken broth, scraping up browned bits with a wooden spoon. Let it bubble for a minute, then stir in heavy cream. Bring to a gentle simmer—watch it closely to prevent overboiling.

Lower heat, add ¾ cup parmesan in small handfuls, stirring until the sauce is silky. If you spot lumps, just stir a bit more or whisk gently; patience is key for a smooth finish.

Toss in spinach and red pepper flakes. Stir until greens wilt—just a minute or so. Taste and adjust salt or pepper, keeping in mind parmesan adds saltiness.

Nestle seared chicken back into the skillet, spooning sauce over each piece. Cover and let everything meld for 3–4 minutes. The sauce will thicken slightly and cling to the chicken.

Meanwhile, cook pasta in well-salted water following package instructions until al dente. Reserve ½ cup pasta water, drain, then add pasta directly to sauce, tossing to coat. Use reserved water to loosen if needed.

Sprinkle remaining parmesan and parsley on top. Serve hot, perhaps alongside a crisp green salad or garlic bread.