Preparation

• In a medium bowl, stir together the mayonnaise, crème fraîche, garlic, parsley, chives, and dill. Squeeze in the juice of one lemon half (reserve the juiced and unjuiced halves for the shrimp), add the Worcestershire, and season with 1/4 tsp. salt and 1/8 tsp. pepper. Cover and chill for at least 1 hour.
• Fill a large bowl with ice water and set aside. Bring a large pot filled with well-salted water to a gentle boil. Squeeze the juice from the reserved lemon half into the pot, and add both lemon halves. Stir to dissolve the salt, and then add the shrimp. Cook, uncovered, until the shrimp are bright pink, 3 to 4 minutes. Transfer to the ice bath and set aside to cool, 10 to 15 minutes. Drain the shrimp, pat dry, and peel, leaving the tails intact. Chill until ready to serve with the dip and crudités.