In a large pot combine 2 liters water, kosher salt, halved lemon (flesh side down), bay leaves, and peppercorns. Bring to a vigorous simmer over high heat.

Once simmering, reduce heat slightly so the liquid is at a steady simmer (not a rolling boil).

Add the shrimp in a single layer and return to a gentle simmer. Cook until shrimp are pink, opaque, and just firm to the touch, about 2 to 3 minutes depending on size.

Prepare an ice bath while shrimp cook: fill a large bowl with the ice and enough cold water to cover.

As soon as shrimp are cooked, use a slotted spoon to transfer them to the ice bath to stop cooking. Chill for 3 to 5 minutes until cold throughout.

Drain shrimp well on a wire rack or paper towels. Refrigerate until ready to serve. Reserve a few whole shrimp with tails on for presentation.

Cocktail Sauce

In a medium bowl combine ketchup, prepared horseradish, fresh lemon juice, Worcestershire sauce, hot sauce (if using), smoked paprika, salt, and black pepper.

Whisk until smooth and taste; adjust horseradish for heat, lemon for brightness, or salt as needed. Chill at least 15 minutes to let flavors meld.

Garnish & Serving

Arrange chilled shrimp around a shallow bowl of cocktail sauce or place sauce in individual ramekins.

Garnish with lemon wedges and sprinkle chopped parsley over the platter. Serve immediately, allowing guests to squeeze lemon over shrimp and dip in sauce.

Store leftover shrimp in an airtight container in the refrigerator for up to 2 days; keep sauce refrigerated up to 5 days.