MARINADE:

1 c. cider vinegar
2 tsp. dry mustard
1 1/2 c. corn oil
1/2 c. tomato sauce
2 tbsp. hot pepper sauce
2 tbsp. Worcestershire sauce
3 tbsp. drained capers
1 tsp. salt
1/2 tsp. black pepper

Marinade: Mix 1 tablespoon cider vinegar with the dry mustard in a large container (not uncoated aluminum) until smooth. Whisk in remaining ingredients. Stir in onions and pepper rings.

2 c. thinly sliced sm. red onions (about 8 oz.)
2 c. thinly sliced bell pepper rings (green, red, and yellow if available)
2 1/2 lbs. (about 48) lg. shrimp, peeled and deveined, leaving tail shell on

Put shrimp in a large saucepan and cover with water. Bring to a boil, cover and boil 1 minute. Remove from heat and let stand 2-3 minutes until shrimp are opaque in center. Drain, then chill under running cold water. Add to marinade. Cover and refrigerate for up to 3 days.