Bring a pot of salted water to a boil and cook the shrimp for 2–3 minutes until pink and opaque. Drain and let cool.
In a large bowl, combine lemon zest, lemon juice, chopped parsley, pickling spice, garlic, red pepper flakes, olive oil, and sliced shallots.
Add the cooled shrimp to the mixture and toss well to coat.
Transfer everything into a glass jar or airtight container.
Refrigerate for at least 1 hour (preferably overnight) to allow the flavors to meld.
Give it a gentle shake or stir before serving.
Serve chilled with bread, crackers, or over a salad.
Enjoy this tangy, flavorful dish straight from the jar!