http://happierthanapiginmud.blogspot.com/2013/06/amish-mustard-pickled-eggs.html?m=1

Pickled Eggs with Mustard–from gazette.com
2 C white vinegar
2 Tblsp mild mustard-I used plain yellow prepared mustard
1/2 C water
1 C sugar
1 Tblsp salt
1 Tblsp celery seed
1 Tblsp mustard seed
6 whole cloves-the spice
1/8 tsp turmeric-optional-my addition to bump up the yellow color naturally
2 onions, sliced thin
12 hard boiled eggs, peeled

1. Add everything except onions and eggs to sauce pan, bring to a boil, mix well (I used a whisk), reduce to simmer for 10 minutes.
2. Remove from heat and cool.
3. Layer onions and eggs in jar, cover with pickle brine.
4. Cover with lid, place in fridge, let marinate at least 24 hours.