Set the oven to 320°F Lightly grease a 9 x 13 pan.
Place all the ingredients for the base in a food processor and whizz together until they form a smooth dough.
Press the dough into the greased pan and prick all over with a fork. Bake for 35-40 minutes until golden and firm. When done, leave to cool.
To make the topping, put the butter, sugar, sweetened condensed milk, and the Lyle’s Golden Syrup in a medium saucepan. Stir over low heat until the butter is well melted.
Let the mixture bubble gently for 5 minutes until it reaches a light golden color, stirring the entire time.
Pour over the toffee all over the cold shortbread in an even layer. Put in the freezer.
Melt the chocolate in a bowl over a saucepan of simmering water.
Take the shortbread out of the freezer. Pour the melted chocolate over the shortbread.
Put the Cambridge Squares back in the freezer and take out when the chocolate has been fully hardened.
Take out the squares and cut. Enjoy eating a little taste of Cambridge!