Season chicken thighs with paprika, chicken rub and salt and pepper to taste.
Melt 2 tablespoons butter in a large cast-iron skillet over medium high heat. Add chicken, skin-side down, and sear both sides until golden brown, about 4-6 minutes on each side; drain excess fat and set aside.
Melt tablespoon butter in the same skillet. Add garlic, and cook, stirring frequently, until fragrant, about 1-2 minutes. Stir in chicken broth, heavy cream, Parmesan, lemon juice and thyme.
Bring to a boil; reduce heat, stir in spinach, and simmer until the spinach has wilted and the sauce has slightly thickened, about 3-6 minutes. Return chicken to the skillet.
Place into oven and roast until completely cooked through, reaching an internal temperature of 165 degrees F, about 25-30 minutes.