Heat the oven to 200 degrees Celsius. Massage pork with salt and pepper. Mix mustard, honey, and thyme in a bowl. Massage half of this marinade into pork. Put pork into baking dish. Chop potatoes into cubes, pour some olive oil, pepper, salt and mix everything up. Put everything into a baking bowl, cover with foil and bake for 25 min. This way the meat will be juicier and softer. Take off foil, flush pork with mustard sauce, decrease the temperature to 180 degrees Celsius and bake for another 20 min. Baking time depends on the size of the pork. Serve how you like and enjoy your meal.