1Fill a medium-sized saucepan with water and bring it to a gentle simmer.
2Add 1 clove of garlic (whole), the finely sliced shallot, the juice of half a lemon with the squeezed lemon half, the bay leaves, and a generous pinch of salt to the saucepan.
3Keep the water at a light simmer and add the raw prawns. Stir gently, reduce the heat to very low, and cover the pan with a lid.
4Let the prawns poach slowly for 5–6 minutes or until just cooked through. Avoid boiling to ensure tender prawns.
5Once cooked, remove the prawns with a slotted spoon and immediately place them in ice water to cool and stop the cooking process.
6While the prawns are cooling, prepare the prawn crackers. For the sauce, combine the mayonnaise, ketchup, Worcestershire sauce, Tabasco sauce, Dijon mustard, and juice of the remaining half lemon in a bowl, mixing until smooth.
7Finely dice the cooked prawns and stir them into the sauce.
8Finely dice 1 stick of celery and add it to the mixture along with the zest of 1 lemon. Stir to combine.
9Finely slice the iceberg lettuce.
10To assemble, place a small amount of lettuce into each prawn cracker, add about 1 tablespoon of the prawn mayonnaise mixture, and garnish with a sprig of curly parsley.