Grease and line the base and sides of an 8 inch square loose bottomed baking tin with baking parchment. The baking parchment is essential as it makes it easier to lift the flapjacks out of the tin once they have cooled.
If you don’t have an 8 inch square tin, use one of a similar volume in size eg 8 x 8 = 64 square inches. I was never good at maths, so I hope you get the idea.
Melt the butter, sugar, and syrup in a large pan over a very gentle heat until all the sugar and butter have melted. DO NOT BOIL THE MIXTURE. This is most likely the reason why some flapjacks turn out hard and difficult to eat.
Add the flour, salt, and oats. Mix thoroughly until everything is covered in the syrup mixture. It helps to give the dry ingredients a little mix before adding to the syrup.
Spread the mixture evenly and firmly into the prepared tin. The mixture is a little runny, but you will still need to press the mixture down firmly as this will help prevent the flapjacks from falling apart after baking.
Bake in the centre of the oven for 25 – 30 minutes or until baked and golden brown in colour.
Remove from the oven. Leave to cool a little before partially slicing the top into bars. DO NOT CUT ALL THE WAY THROUGH. You need the flapjacks to set and cool completely before doing that.
The mixture will still be hot and very sticky, so take care, especially when baking with children.
Now that the flapjacks have cooled completely, you can complete to process of slicing them into bars. They will feel soft and chewy. And should not fall apart.
Keep in an airtight container with a sheet of baking parchment wrapped around them, to help keep them moist and chewy.
Notes
WHY DO MY FLAPJACKS FALL APART?
There could be many reasons why your flapjacks may fall apart after baking. I find using Porridge Oats rather than whole jumbo oats are better.
Slicing them into bars while still warm can often cause them to fall apart. If you partially slice them and pop them in the fridge, this will speed up the cooling process.
I know I’m probably stating the obvious, but did you weight the ingredients correctly?
Packing the mixture down firmly in the baking tin before baking also helps. This removes the possibility of any air being trapped in between the oats, causing them to fall apart.
WHY ARE MY FLAPJACKS SO HARD?
Over boiling the sugar, butter and syrup, is one possible reason for flapjacks being so hard. Simmering the butter, sugar, syrup mixture on low heat is better.
Adding flour helps make them chewy and soft. If you missed the flour out, that could be the reason.
If they do turn hard, leave them in the open air for a few hours to help soften them a little.
SHOULD I CUT FLAPJACK HOT OR COLD?You should ideally wait until the flapjacks have cooled down completely before you slice them. But as mentioned above, you can score the top of the flapjacks when they have cooked a little, but wait until they have cooled completely before slicing the flapjack bars all the way through.SHOULD FLAPJACKS BE SOFT WHEN THEY COME OUT OF THE OVEN?Flapjacks will appear to be soft when you first take them out of the oven. They are not underbaked, so don't worry about that. They will firm up but still have a deliciously chewy texture, once they have cooled down.