How to Make It
In a large stock pot, add water, Old Bay, salt, and lemon juice. Bring to a boil. Add sliced onion, garlic, and fennel. Allow to cook until tender, approximately one minute. Remove onion, garlic, and fennel, and place on a sheet tray to cool.
Add shrimp to boiling liquid and cook for about 2 minutes, or until just cooked through. Remove shrimp from the liquid and place on a sheet tray. Refrigerate until cool. Once shrimp and vegetables are cool, mix the vegetables and shrimp in the remaining ingredients to marinate. Add to jars, and top with remaining marinade. Save in the fridge for up to 2 days.