- Add 3 quarts water to a large, stainless steel pot. Add half the boiling spice, 1 bay leaf, 3 garlic cloves, celery, and a small handful of salt. Bring to a boil over medium-high heat, then reduce heat to a simmer and cook 10 minutes. Increase heat and add shrimp, cover, and cook 2 minutes. Drain, rinse under cold running water, peel, and devein the shrimp.
- In a saucepan over medium-high heat, bring vinegar, onions, remaining bay leaf, spice, and garlic to a full boil. Reduce heat to low and simmer 5 minutes. Turn off heat. Let mixture cool slightly then pour over shrimp. Add lemon zest and juice and toss well. Let cool completely, then cover and transfer to refrigerator. Let shrimp marinate for at least 4 hours before serving. They will keep in fridge up to 2 weeks.