Bring the stock to the boil (if crab stock unavailable use fish stock with a good pinch of saffron).
Turn down to a simmer add fish and prawns.
After thirty seconds add mussels, clams, bugs and or marron, fennel, saffron and potatoes.
After another thirty seconds or when mussels start to open add scallops.
When everything is cooked (approximately one minute) use a slotted spoon to place the seafood and vegetables onto a slice of grilled sourdough, reserving the liquid in the pot.
Return stock to the high heat and reduce by half.
Take off heat and whisk in the aioli and a squeeze of lemon, season with salt and pepper, and pour over seafood.