This is not a recipe for the timid cook! It requires you to pay attention the whole time and the pan gets incredibly hot, so you need to take care. The key to making sure it doesn't burn is to keep stirring the entire time.
There are only two pieces of equipment you need, but using the right tools will make this recipe much easier. Use a flat-bottomed spatula. I use a silicone one and it means you can keep scraping the bottom of the pan and get into the corners easily. Secondly, use a large saucepan with a thick base. The thick base will ensure the pan can hold the heat it needs. Choose a pan that is larger than you probably think you will need as this will make the stirring easier and make sure you don't have any spills. Believe me, you don't want to be cleaning this stuff off your hob!
In: Sweet Snacks
I used a large tray (32x19cm) and you'll notice from the picture that it still makes a pretty thick layer of caramel and quite a hefty snack! On my second attempt I split this amount across two trays and found that it gave a better thickness. Since it doesn't make sense to use half a can of condensed milk, I'd recommend making two trays per one lot of caramel.
This recipe is just for the caramel part because it's the trickiest bit. You can put this caramel on a number of different tray bakes:
To finish off, melt a 200g bar of dark chocolate (per tray) and spread it over the top. Leave to set before removing from the tray and slicing into squares.
If you are making two trays as I have suggested, than you will probably find that's rather a lot to have on the go at once. Both the shortbreads and flapjacks can be frozen for a few months if that helps.