Preheat oven to 350.
Pat the porkchops dry on both sides with paper towels. Season with 2 tablespoons of the pepper and 2 teaspoons of the salt.
Heat the grapeseed oil in a large stainless-steel or cast-iron pan over high heat. When the pan is very hot and the oil begins to shimmer, add the pork chops and cook, undisturbed, until golden brown, about 3 minutes. Flip the pork chops over and cook until golden brown, about 2 minutes. Turn the pork chops so that the fat cap is touching the pan and cook, undisturbed, until golden brown, about 1 minute. Set the pork chops flat in the pan and transfer it to the oven. Cook until the internal temperature reaches 140 F, about 8 minutes. transfer the pork chops to a cutting board to rest while you make the pan sauce.
Set the pan over medium heat. Add the butter, shallot, and garlic to the pan and cook, stirring, until the butter has melted, about 1 minute. Add the cream, mustard, and remaining 1 teaspoon pepper and stir to combine. Cook until slightly thickened, about 1 minute. Add the vinegar and remaining 1/2 teaspoon salt and stir to combine, about 30 seconds. Remove the pan from the heat.
Serve the pork chops with the sauce poured over the top.