Created by ImPat on March 9, 2019
Step 1: Put aioli, mustard powder and vinegar into a medium bowl and stir to combine and then fold in crabmeat and season.
Step 2: Using a serrated knife, cut a deep lengthways slit into each roll, taking care not to cut all the way through and gently pull each roll open and fill with watercress and top with crab mixture, onion and caviar.
Step 3: Serve with lemon wedges on the side.