I pressed the mixture into a shallow baking tray that I'd lined with greaseproof paper (for ease of removal). The mix goes sticky very quickly, so I used a knife dipped in the hot water from the pan to help with spreading. The tray went in the fridge for an hour or two to make sure everything was properly set. I then lifted the set krispie block from the pan using the paper and cut it into 18 pieces with a sharp knife. To prevent the bars sticking to each other, we wrapped them all in a piece of greaseproof paper "just like in the shop" according to my son.