If the shrimp are raw, they need to be boiled in salted water with white wine or in vegetable broth with wine. Let them cool slightly and then peel them (photo 1).
Mix ketchup with mayonnaise (photo 2), adjusting the proportions to taste. Pour the sauce over the peeled shrimp (photo 3). Mix well (photo 4).
Place the shrimp cocktail on a bed of lettuce leaves (photo 5). Be sure to rinse and dry the leaves beforehand. Serve with lemon wedges. The shrimp cocktail can be drizzled with lemon juice before serving.
Notes
The shrimp cocktail can be stored in the refrigerator under a lid for no more than a couple of days. For the best taste, it's ideal to use homemade mayonnaise for the sauce.