My wife, Ali, and I always stop at Mustards Grill in Napa during our trips to wine country and eat this dish ritualistically. It really is the best pork chop I've ever eaten. I needed to crack the code and figure out the recipe. Here's my version of Cindy Pawlcyn's dish and I hope you love it as much as I do.
For the pork and marinade: Place the pork chops in a 1- gallon resealable plastic bag. Combine the remaining marinade ingredients (except for the neutral oil) in a mini food processor and process until incorporated, or whisk together in a medium bowl. This will be your marinade and glaze.
Coat the pork chops liberally with the marinade and marinate for 3 hours and up to overnight in the refrigerator.
Prepare a grill by heating one side to high and the other to low. Alternatively, heat a large grill pan over 2 burners -- one on high heat and the other turned off. Clean and grease the grates.
Remove the chops from the bag and reserve the marinade for basting. Blot the chops with paper towels, then grill, undisturbed, until you have a great grill mark on each chop, 4 to 6 minutes. Baste with the reserved marinade then rotate a quarter turn and grill until you have a nice crosshatch mark, another 4 to 6 minutes. Flip over and repeat the grilling, basting and turning.
Start to take an internal temperature after both sides are grilled and basted. If you don't hit 165 degrees F, move the pork chop to the cooler side and cover to create a convection oven. The pork is ready when it registers 165 degrees F on an instant-read thermometer. Remove from the heat and let rest for 5 minutes.
Meanwhile, make the mustard sauce: Stir together all of the ingredients in a small bowl. Add 1 to 2 tablespoons water, if needed, to thin the sauce.
Drizzle the mustard sauce over the pork chops or serve on the side for dipping.