Preheat a medium saucepan over medium heat.
Add the black peppercorns and cook, while shaking the pan occasionally, until the peppercorns are toasted and fragrant, about 2 minutes.
Transfer the peppercorns to a spice grinder and allow them to cool slightly, about 5 minutes.
Process the peppercorns until they are finely ground, about 15 seconds.
In a medium saucepan over medium heat, add the ground peppercorns, the vinegar, the mustard, and the butter and stir to combine.
Bring the vinegar mixture to a simmer, while whisking occasionally.
Add the light brown sugar, the ketchup, the crushed red pepper, the thyme, the bay leaf, the shallots, the garlic, and 1 tablespoon of the kosher salt to the vinegar mixture and whisk to combine.
Cook the vinegar mixture, whisking constantly, until it begins to simmer, about 1-2 minutes.
Cover the saucepan and reduce the heat to low.
Simmer the vinegar mixture, stirring occasionally, until the flavors meld together, about 20 minutes.
Uncover the saucepan and transfer it from the heat.
Allow the sauce to cool to room temperature.
Reserve 1/2 cup of the sauce in a small bowl, storing it in the refrigerator until ready to use.
In a baking dish, add the pork chops and the remaining sauce, turning the chops to coat them well.
Cover the baking dish and refrigerate the pork chops for 12 hours.
Transfer the pork from the marinade, discarding the marinade in the baking dish.
Rinse the pork chops under cold water, then pat them dry.
Transfer the pork chops to a large plate and allow them to stand at room temperature for 30 minutes.
Sprinkle the pork chops evenly with 1 1/2 teaspoons of the remaining salt and 1/4 teaspoon of the black pepper.
Preheat the grill to medium-high heat.
Using the neutral-flavored oil, grease the grill grates.
Add the pork chops to the hot grill and cook over direct heat, flipping the pork chops once, until the pork just begins to brown around the edges and along the bones, about 2 minutes per side.
Transfer the pork chops to indirect heat and cook, covered and flipping once, until the thickest portion of the pork chops reach an internal temperature of 140 degrees F, about 25-20 minutes.
During the final 5 minutes of grilling time, baste the pork with the reserved sauce.
Loosely tent the pork chops with foil and let them rest until they reach an internal temperature of 145 degrees F, about 10 minutes.
While the pork chops are cooking, preheat a small Dutch oven over medium heat.
Add the onions, the olive oil, the remaining kosher salt, the ground nutmeg, and the remaining black pepper to the Dutch oven and cook, while stirring constantly, until the nutmeg is fragrant, about 1 minute.
Add the muscadine wine, the fish sauce, and the dark molasses to the onion mixture and stir to combine.
Increase the heat to medium-high and bring the onion mixture to a simmer.
Simmer the onion mixture, while stirring occasionally, until the onions are tender and the liquid is reduced and glazes the onions, about 40-45 minutes.
Serve the pork chops with the braised onions.