Peel, wash and slice the potatoes. Bring to the boil in a pot with herb butter, rosemary, 150 ml water and stock. Cover and simmer for about 10 minutes.
Preheat the oven grill. Clean, wash and cut the peppers into strips. Add to the potatoes with frozen peas and cook for another 5 minutes. Wash the meat and dab dry. Heat the oil in a large pan. Fry the smoked pork loin on each side. Remove and place on a baking tray.
Mix mustard and breadcrumbs. Spread the smoked pork loin with it and gratinate under the hot grill of the oven for 3-4 minutes. Season vegetables with a little pepper. Arrange everything.