Bring plenty of water with bay leaves, peppercorns and peeled, halved onions to the boil. Cook the smoked pork loin in it at medium heat for about 45 minutes. In the meantime peel, wash and slice the kohlrabi.
Clean and wash the sugar peas. Wash the parsley and, except for a few leaves for garnishing, cut into fine strips. Wash potatoes carefully, then cook in boiling salted water for 15-20 minutes.
Steam kohlrabi and sugar peas in 1/4 litre salt water and 1/2 teaspoon sugar for 10-15 minutes. Stir in crème fraîche and parsley. Flavour with salt, pepper and possibly some more sugar.
Slice the smoked pork loin. Arrange garnished with parsley.