Wash the cucumber thoroughly, rub dry and cut in half lengthwise. Remove seeds, cut flesh into small cubes. Clean and wash the salad (put some leaves aside for garnishing) and cut into strips. Drain asparagus, drain well and cut into small cubes. Rinse crab flesh cold and dab dry. Whip cream until semi-solid.
Mix ketchup, mayonnaise and cognac. Fold in the cream. Season sauce with salt and pepper. Mix all ingredients with the sauce. Line four cocktail glasses with lettuce leaves, fill in crab cocktail. Garnish with prawns and basil