Mustard Pickled Eggs

12 eggs, hard boiled
2 cups apple cider vinegar
2 tablespoons mild prepared mustard
1 cup granulated sugar
1/2 cup water
1/2 tablespoon salt
1 tablespoon celery seed
1 tablespoon mustard seed
6 whole cloves
2 onions, sliced

Boil 12 eggs and remove the shells carefully; set aside.

Combine remaining ingredients, except onions, in a small kettle. Simmer 10 minutes. Cool.