Gather your supplies.
Grease and line a 3cm deep, 16cm x 26cm slice pan with baking paper. Be sure to leave some overhanging the edges.
Place half the condensed milk, sugar, glucose syrup, golden syrup and butter in a heavy based saucepan over low heat.
Cook, stirring, for 4-5 minutes or until the sugar has dissolved.
Increase heat to medium-low, bring to a simmer and cook for 4-5 minutes or until mixture thickens slightly.
Remove from heat and stir in half the chocolate - you'll need to work quickly here.
Spread evenly in pan - again, you need to work quickly before it cools too much.
Smooth the top - take care if you use your fingers as it is REALLY hot - and set aside for 20 mins.
Lightly dust a flat surface with icing sugar and knead fondant until smooth, gradually adding the vanilla - add more icing sugar if needed.
Roll fondant out between 2 sheets of baking paper to being 5mm thick.
Cut fondant to the same size as your tray and carefully place on top of the caramel mixture. Press down lightly to secure.
Repeat the steps for making the caramel - Place the remaining condensed milk, sugar, glucose syrup, golden syrup and butter in a heavy based saucepan over low heat.
Remove from heat and stir in half the chocolate.
Quickly spread over the top of the fondant layer...
Smooth as much as possible and set aside for 20 minutes to cool slightly.
Cover in plastic wrap and refrigerate until firm - overnight is best.
Remove from pan and trim edges.
Cut into roughly 2cm pieces - you need to keep them quite small as they are very sweet.
And you're done! Enjoy!