This comes from the excellent list of mussel recipes over at penncoveshellfish.com. Nice unexpected choice for a potluck.

This is a favorite recipe for either our Penn Cove Mussels or our Mediterranean Mussels that is very simple to prepare and provides a good use for mussels if you steamed up too many for dinner or if you just want a delicious mussel appetizer.

There are an average of 25 mussels to the pound for farmed mussels and 20 to the pound for wild mussels. Whenever possible, use farmed mussels like ours for better flavor and to insure that you will not find any sand or grit.

4 pounds of steamed Penn Cove or Mediterranean Mussels
1/2 gallon of cider vinegar
2 1/2 cups sugar (rule is 3 to 1 on the cider-sugar mix)
1/2 sliced red onion
1/2 cup chopped scallions
2 T  diced pimentos or red bell pepper
2 T chopped garlic
2 T extra virgin olive oil

Appetizers for twenty of five mussels each

Store the live mussels in your refrigerator and cover with ice or a damp cloth to keep moist. They should not stand in water, so drain liquid from the container daily.

Usually the mussels will be de-bearded when purchased, however, if the mussels still have their “beards”, wait until within an hour of cooking to remove the mussel beards by giving them a sharp pull toward the pointed tips of the mussels. Lightly rinse the mussels under fresh, running water before cooking, then set aside. If any mussels are gaping open, they are getting weak, discard any that will not attempt to stay closed after squeezing their shell shut or if they have broken shells or an “off’ odor.

Steam 4 pounds of debearded mussels following classic steamed mussel recipe. Remove mussels from broth and set in a large bowl in the refrigerator to cool, you may leave the mussels in the shells.

Prepare the marinade by mixing the sugar with the cider until dissolved. Stir in the red onions, scallions, pimentos, olive oil and garlic to the marinade.

Leave the mussels in their shell in the bowl and pour the marinade over the top only after mussels have cooled completely. Drain marinade from bowl and pour over mussels several times until all mussels are soaked. Cover bowl and keep cool until mussels are to be used.

Mussels should sit in marinade at least an hour before serving and may be kept in marinade up to a week. Pour marinade over mussels right before serving. Serve by themselves or add to a salad for a great treat.