Quarter the onion and put it in a pot with the smoked pork, peppercorns, bay leaves and juniper berries.
Add water and vinegar and bring to a boil. Simmer at medium heat for 1 hour. Remove the pot from the heat and let everything cool down. Remove the meat from the pot and strain and collect the broth.
Cut the pork loin and red onions into fine slices, arrange them nicely on plates or a platter and finally pour some of the broth over them. Serve with good farmhouse bread.
It is best to prepare it a day in advance.