Serves 8

Prep time 1 hr, cook 25 mins (plus chilling, cooling)

For shallot vinegar dressing, stir vinegars and sugar in a small saucepan over medium heat to dissolve sugar, then remove from heat. Add shallots and set aside to cool.

For mayonnaise, process yolks, lemon juice and mustard in a food processor until smooth. With motor running, gradually add combined oils in a thin steady stream until thick and emulsified. Season to taste and refrigerate until required. Makes 450ml.

Bring a large saucepan of salted water to the boil. Add crab, cover and bring back to the boil, then remove lid and cook until crab is just cooked and bright orange (10-12 minutes). Remove from water, set aside. Bring water back to the boil, then add marron and cook until just cooked and red (3-5 minutes). Remove and set aside. Bring water back to the boil, add yabbies and cook until just cooked and bright orange (2½-3 minutes), remove and set aside.

Divide mayonnaise among two bowls, add herbs to one, stir to combine, season to taste. Add tomato sauce, Tabasco and Worcestershire sauce to remaining mayonnaise, stir to combine, season to taste.

Scatter rock salt or crushed ice over serving platters and arrange seafood on top. Serve with herb mayonnaise, cocktail sauce, shallot vinegar dressing and lemon wedges.