Grilled Pork Tenderloin Drenched with an Onion Sauce

The simple marinade that coats this pork tenderloin is as yellow as prepared mustard and when grilled, creates a crusty coating around a tender interior. The pork is served atop a mound of fluffy garlic mashed potatoes. The spinach surrounding it all provides both color and a tender texture. The simple onion sauce that drenches everything brings it all together with every moist, succulent, yummy bite.