Preheat oven to 425°F. Season pork chops lightly with salt and pepper. In a small bowl, combine mustard, mustard powder, French thyme, and garlic; mix well and spread evenly over both sides of the chops. Heat the oil in a large skillet over medium-high. Add the chops and brown for 2 minutes per side. Transfer your skillet to the oven and cook for an additional 5-8 minutes, until no longer pink and cooked through. Serve over sauteed baby spinach.