If you really want to pimp it up lol - whizz a peanut bar into crumbs - if you don't have a food processor then just chop it up a bit and zap in the microwave for a few seconds so you can squash it down a bit. Divide between two dishes.
Make a mix-a-mousse out of half a toffee & walnut and half a banana shake. Pour on top of the peanut bar crumbs, dividing evenly between the two dishes, and let it set. You can almost pretend it's banoffee pie...
Another nice variation is to make the mousse out of half a choc shake and half a vanilla shake, mixed with the peanut bar it's almost ferrero rocher-y.
Obviously this makes two servings - my CDC said it's ok to mix the mousse in advance (don't leave it for days though lol) - the 15min rule is only because the shakes/soups change texture/separate rather than lose vitamins, but you don't get that problem with the mousse.