Pat and season the chicken. Pat the chicken thighs dry with paper towels. Season both sides generously with salt and pepper. Dry skin equals crisp skin later.

Brown the thighs. Heat olive oil in a large skillet over medium-high heat. Place the thighs skin-side down and cook until the skin is golden and crisp, about 7–9 minutes. Flip and cook another 4–6 minutes. Transfer to a plate; they’ll finish in the sauce.

Sauté aromatics. Reduce heat to medium. Add butter, then the shallot. Cook 2 minutes until soft. Stir in garlic and red pepper flakes; cook 30 seconds until fragrant. Don’t let the garlic brown.

Deglaze the pan. Pour in white wine, scraping up browned bits. Let it simmer 2–3 minutes to reduce by about half. Add chicken broth and Italian seasoning. Simmer another 2 minutes.

Add cream and Dijon. Stir in heavy cream and mustard. Bring to a gentle simmer. The sauce should look smooth and slightly thickened, about 3–4 minutes. If using half-and-half, simmer a touch longer.

Wilt the spinach. Add the spinach in batches, stirring until it just wilts. Don’t overcook; you want it vibrant.

Return the chicken. Nestle the thighs into the sauce, skin-side up. Reduce heat to medium-low, cover, and cook 8–10 minutes, until the chicken reaches an internal temperature of 175°F for tender, juicy dark meat.

Finish with lemon and Parmesan. Stir in Parmesan, lemon zest, and lemon juice. Taste and adjust seasoning with salt and pepper. If the sauce is too thick, add a splash of broth; if too thin, simmer uncovered 1–2 minutes.

Serve. Spoon sauce and spinach over the chicken. Garnish with chopped parsley. Pair with rice, mashed potatoes, buttered noodles, or crusty bread to catch every drop.