Line a 9x9inch deep square tin with parchment paper. Melt the butter in a bowl until smooth.

Add crushed shortbread biscuits to a bowl and add the melted butter, and mix together.

Firmly press the mixture into the bottom of tin and refrigerate for now.

In a large bowl pour the condensed milk, butter, sugar, and golden syrup and melt in 1 minute bursts in the microwave for 10-12 mins in total. Stir/beat the mixture well each time, carefully, until the mixture has thickened into caramel. 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 white chocolate and dark/milk chocolate, pour over the caramel – swirl together.

Chill the shortbread back in the fridge for another 1-2 hours until the chocolate has set. Chop your shortbread into the separate pieces and enjoy!