Preheat your oven to 180C/160C Fan, and line a 9x9inch deep square tin with parchment paper.
Cream together the sugar and butter in a stand mixer with the paddle attachment until smooth – mix in the flour until a dough is formed. It will be crumbly but the ingredients will be evenly dispersed!
Firmly press the mixture into the bottom of tin and bake in the oven for 20-25 minutes until pale golden on top!
Once baked, remove from the oven and leave to the side. In a large saucepan pour the condensed milk, butter, sugar, and golden syrup and melt on a medium heat until the sugar has dissolved – stir frequently to stop anything from catching.
Once the sugar has dissolved, turn the heat up high and let the mixture come to boiling point and boil for 5-7 minutes stiring constantly so that the mixture doesn’t catch. BE CAREFUL as the mixture is VERY hot and can burn you if it splashes back!
The mixture will be ready when it has changed to a slightly darker golden colour, and has thickened to a soft fudge texture!
Pour the caramel onto the shortbread base and leave to set for an hour in the fridge.
Once set, melt the milk chocolate and pour over the caramel – melt the white chocolate and pour over too - swirl it into the milk chocolate with the end of a cake skewer so it forms a pretty pattern.
Chill the shortbread back in the fridge for another 1-2 hours until the chocolate has gone hard**!
Chop your shortbread into the separate pieces and enjoy!
This will keep in an airtight container for at least 1 week – if they last that long!
If you can't access golden syrup, you can give corn syrup or honey or similar a go, but I have not tested these as much. Alternatively, you can use my millionaires flapjacks caramel!
If your caramel is rock solid when you remove it from the fridge, you have slightly over done it. Not to worry though, when you pour the chocolate on, leave it to set at room temperature rather than in the fridge and it should soften the caramel slightly.
**If you struggle to cut your shortbread and tray bakes without the chocolate cracking on top, set it at room temperature rather than in the fridge and it’ll be softer so therefore won’t crack when you cut it!