Boil shrimp in large pot of salted water 2-3 minutes until pink and opaque. Drain; immediately ice-bathe to stop cooking.

Whisk ketchup, horseradish, lemon juice, and Worcestershire smooth in medium bowl; refrigerate until needed.

Spoon about 2 tablespoons sauce into each cup bottom.

Hook 2 shrimp over each rim.

Garnish each with small dill or parsley sprig and tiny lemon wedge.

Refrigerate until serving, up to 4 hours ahead.