Step 1

Note: When using larger or smaller shrimp, increase or decrease cooking times for shrimp by one to two minutes, respectively.

Step 2

Bring reserved shells, 3 cups water, and salt to boil in medium saucepan over medium-high heat; reduce heat to low, cover, and simmer until fragrant, about 20 minutes. Strain stock through sieve, pressing on shells to extract all liquid.

Step 3

Bring stock and remaining ingredients except shrimp to boil in 3- or 4-quart saucepan over high heat; boil 2 minutes. Turn off heat and stir in shrimp; cover and let stand until firm and pink, about 8-10 minutes. Drain shrimp, reserving stock for another use. Plunge shrimp into ice water to stop cooking, then drain again. Serve shrimp chilled with cocktail sauce.

Step 4

FOR COCKTAIL SAUCE: Stir all ingredients together in small bowl; adjust seasonings as necessary.