Clean and wash the dogfish, making sure to take out the livers and keep them aside. Cut the dogfish in small pieces. Fill a pot with water and add the white wine vinegar, the stems of parsley and half of the bay leaves and bring it to the boil. Once boiling, throw in the chunks of dogfish and place a lid, then turn the fire off and leave it to cook for 10 minutes. Fry the garlic and parsley in extra virgin olive oil, then add the livers and squash them with a wooden spoon. Add the walnuts and the remaining bay leaves. Blend with the apple vinegar and white wine and cook for about 15 minutes. In a bowl, place the dogfish and cover it with the hot sauce. Cover it and once cold let it rest in the fridge for 24 to 48 hours before serving.