WATCH James make his caramel sauce in our YouTube tutorial video: 1. Preheat your oven to 160°C/140°C fan/Gas 3. Line an 8-inch square brownie tin with baking paper and grease the sides. 2. To make the shortbread, use a wooden spoon to combine the butter with the sugar in a large bowl until it forms a paste. Add the flour and gently mix it all together. Use your hands to work the mix until it mops up all the crumbs – you don’t need to add any extra liquid. 3. Press this out flat with your hands so that it fills your lined tin, then bake for 10–15 minutes or until it is just blushing golden brown at the edges. Leave to cool in the tin. 4. Whilst it’s baking, start the caramel. Weigh all the ingredients into a saucepan and place on a medium-high heat, stirring gently. Watch it closely as you stir – you should start to see little slivers of brown where it has stuck to the bottom of the pan. If you see these bits, stir them in vigorously and turn the heat down to low-medium. Simmer gently until it is a colour that you like – I go for a deep, golden brown. 5. When ready, pour your dark caramel onto your biscuit base and spread it over the top with a knife. To even out the surface, pick up your tin and drop it onto the countertop with a bang. Leave this to cool for at least an hour (or overnight) before adding the chocolate topping, or the heat will ruin your careful chocolate work. 6. Break about three-quarters of the chocolate into a microwaveable bowl and chop the rest very finely. Zap your chunks in a microwave on full power for 15 seconds at a time, stirring in between (or melt over a bowl of simmering water). Once melted, add your finely chopped chocolate and stir until they are combined. 7. Pour it onto your cooled caramel surface and spread gently with a knife. Again, to even the surface, pick it up and drop it onto your countertop, or give it a shake in the tin. If you like, you can lay a sheet of cling film on top of your chocolate for an extra shiny surface, but pull it tight to get rid of the wrinkles. Leave it to set for another hour (NEVER in the fridge), before slicing into squares. Heat your knife with water from the kettle to make slicing easier.