Prepare the first stage of the batter for the beignets: Whisk together the flour, water, warm beer, olive oil and egg yolk to form a smooth batter. Clean down the sides of the bowl and cover with cling-film to prevent a skin forming. Allow the batter to stand at room temperature for 1 hour.
Shuck all 18 oysters and remove from the shells, saving the oyster juice for the vichyssoise. Pic