Michigan State University Extension
Preserving Food Safely - 01600592
10 lb. cured herring Prepared mustard Dill pickles, one piece for each fillet 1 quart vinegar (5% acidity) 1/2 lb. onions, sliced 2 tablespoons sugar 1/4 cup bay leaves 2 1/2 tablespoons mustard seed 2 1/2 tablespoons whole cloves 3 tablespoons whole black pepper 3 tablespoons cracked ginger 3 tablespoons cracked cinnamon
Cut cured herring into two fillets, removing the backbone. Spread each fillet with mustard. Roll each fillet around a dill pickle and fasten with a toothpick. Pack the rolls on end in a crock.
Mix together vinegar, sliced onions, sugar and spices. Simmer, do not boil, sauce for 45 minutes. Strain out the spices and onions to pack among the layers of rollmops. Cool the sauce and pour over fish to cover. Allow to stand 2 to 3 days in refrigerator before using. Rollmops should keep for several months.