1 lemon

1/2 small onion, sliced thin

2 tbsp. vegetable oil or olive oil, optional

1/4 cup white vinegar or white wine vinegar

1 tbsp. Old Bay seasoning

1/2 tsp. seasoning salt or plain salt

1 tsp. minced garlic

1 tsp. sugar

1 tsp. mustard seed

1/2 tsp. crushed red pepper or cayenne pepper

1 tsp. dried parsley flakes

4 bay leaves

1/2 tsp. celery seed

1 tsp. black pepper corns

Using a wide mouth quart canning jar or other large container with a tight fitting lid, thinly slice half the lemon and set aside; squeeze the juice from the other half of the lemon into the jar and drop the squeezed lemon into the bottom of the jar. Add some of the onion slices and a bay leaf and a lemon slice, 1/4 of the shrimp and continue layering until all the lemon slices, onion, bay leaves and shrimp is used. 

Add the oil if using, Old Bay seasoning, seasoning salt or plain salt, minced garlic, sugar, mustard seed, crushed red pepper or cayenne pepper, parsley flakes, celery seed and black pepper corns. Pour vinegar over all and fill with cold water to cover the shrimp. Cover jar or container with lid and shake to distribute spices throughout the jar and refrigerate until chilled, up to 5 days, if they last that long. 

They're better after they marinate at least 24 hours. Recipe may be doubled, and you may use any size shrimp and tweak the recipe to suit your tastes.