Preheat oven to 375 degrees F. Brush pork with mustard and sprinkle with salt, pepper and half the rosemary. Place in a small roasting pan. Arrange vegetables in a casserole.
Pour in stock, sprinkle with salt, pepper and remaining rosemary, and then cover. Roast pork and vegetables 60-70 minutes, or until pork reaches an internal temperature of 165 degrees F and the vegetables are tender. Let pork rest 10 minutes before thinly slicing and serving with vegetables arranged alongside.