This hearty sheet pan supper is a cinch to make, even on the busiest weeknight. The secret to crisp, breaded pork chops? Dredge only one side of each pork chop in the panko mixture to keep the underside of the meat from becoming soggy.
Preheat oven to 425°F with oven rack 6 inches from heat. Stir together mustard, thyme, rosemary, pepper, and 1 1/2 teaspoons of the salt in a small bowl. Reserve 2 teaspoons of the mixture.
Stir together panko, 2 tablespoons of the oil, and 1 teaspoon of the salt in a shallow dish. Rub pork chops with mustard mixture, and dredge 1 side of pork in panko mixture, pressing to adhere. Place pork on a baking sheet lined with aluminum foil, with dredged side facing up.
Toss together potatoes, shallots, 1 1⁄2 tablespoons of the oil, and remaining 1/2 teaspoon salt in a bowl. Arrange potato mixture around pork chops. Bake in preheated oven until a thermometer inserted in thickest portion of pork registers 118°F, 18 to 20 minutes.
Increase oven temperature to broil. Toss haricots verts with 1 tablespoon of the oil, and scatter around pork chops. Broil until pork registers 135°F and vegetables are tender, about 5 minutes. Let pork rest 10 minutes (internal temperature will increase to 145°F). Whisk together vinegar, reserved 2 teaspoons mustard mixture, and remaining 2 tablespoons oil; drizzle over vegetables.