One tin sardines, preferably in oil dressing, because they're apparently good for you.
Three slices of bread to mask the taste of the sardines.
CHUNKY peanut butter to mask the flavour, smell and crunchiness of sardine spines.
Nutella because if something can't be improved with Nutella, it can't be improved.
Stack them up and enjoy the taste sensation that's sweeping the nation, although not sure that the milkshake version will be quite as successful.