Preheat the oven at gas mark 5 for crunchy flapjacks or gas mark 2 for chewy ones

Line a baking tray/tin (20 cm x 30 cm recommended, but a bit smaller will work) with baking paper. I find it works fine without this step if you use a non-stick tray.

Melt the butter, sugar, a pinch of salt, and syrup in a pan. Mix to combine

Bring off the heat when it's a liquid and add the oats.

Mix in the oats in the pan. Make sure the pan is big enough to allow you to mix the ingredients properly as I think a smaller pan will mean you can't get the liquid mixture mixed in properly.

Add the mixture to the baking tray and press evenly.

Bake for 25 minutes at gas mark 2 for chewy flapjacks. For crispy flapjacks bake at gas mark 5 for 30 minutes. Use your best judgement here for what time and temperature suits you. I used gas mark 3 for 30 minutes, but I think that (or too small a pan) caused uneven binding and a softer bottom so I had to wait a while for them to set properly)

Remove from the oven and cut after a few minutes. Do not serve yet, but allow to cool completely. I found putting them in the fridge after they'd cooled helped them bind solidify properly.