I used this recipe and it's amazing :O I changed one thing, instead of using 250g normal white sugar, I used 100g white and 100g dark brown which works out to be quite sweet.
I had one problem though, my tin wasn't big enough the which meant middle hadn't set properly so I cut around the edges and put it back inside for another 10 minutes. It's cooling now but time will tell. The edge pieces came out sooo good. Not cakey at all, crackly on top and nice and firm with sticky centres omnomnom