Peanut butter flapjack updates the classic oat bar with peanut butter and jelly flavours. Oaty. Syrupy, nutty and fruity - all in one bite.This recipe makes sufficient to fill one 8 inch/ 20cm round baking tin. I used grape jelly, but seedless raspberry jam is a great alternative if you cannot get hold of this. Don't be tempted to add more jam as this will mean it bubbles up and 'leaks' through the top of the flapjack during baking.