The mustard-wine mixture reduces while the pork roasts,forming a simple pan sauce to drizzle over the meat.
Preheat oven to 450 degrees. Whisk together wine, water, andmustard. Season pork on all sides with salt and pepper.
Heat a 12-inch ovenproof saute pan over medium-highheat; add oil. Sear pork until browned on all sides, about 6minutes total. Remove from heat. Carefully add mustard-winemixture. Transfer pan to oven.
Roast pork, spooning sauce over meat about halfwaythrough, until an instant-read thermometer inserted intothickest part of meat registers 145 degrees, about 15 minutes. Let pork rest for 10 minutes before slicing. Drizzle with sauce.