How to Make It
In a large saucepan, combine 1 gallon of water with the 8 lemon wedges, the bay leaf, peppercorns, Old Bay and 1 teaspoon of salt and bring to a boil. Add the shrimp and return to a boil. Remove from the heat, cover and let the shrimp poach until just opaque throughout, about 5 minutes. Drain and rinse the shrimp with cold water, then refrigerate until chilled, 30 minutes.
In a medium bowl, mix all of the remaining ingredients and season with salt and pepper. Cut 12 of the shrimp into 1-inch pieces and fold them in. To serve, spoon the chopped-shrimp salad into 6 glasses or bowls and top with the remaining whole shrimp. Garnish with freshly grated horseradish and lemon wedges.