Add the cold, cubed butter and rub in until a crumb is achieved. It's normal for it to go clumpy, as long are there are no lumps of butter.

Tip the dough out into a well-greased, non-stick, medium roasting tin. Spread evenly and press down firmly with the flat of your hand.

Prick the dough all over with a fork - this helps to stop the biscuit puffing up during baking.

Bake for 25-30 mins or until firm and pale golden.

Allow to cool until firm. You can then either leave in the tin to cool completely or, if you want to speed the process up a bit, you can carefully tip the biscuit onto a cooling rack, then return it to the tin once cool.

Mix the caramel and biscoff together in a bowl.

With the cold biscuit layer in the tin, spoon the biscoff caramel on top and spread gently to the edges.

Pop the tin in the fridge to firm up for 15 minutes.

Cover and place in the fridge to set for 30 minutes or until the chocolate is set all the way to the centre. .

Run a knife around the edges of the tin and turn out onto a board.

Trim the top and bottom off with a sharp knife to create a neat rectangle, then cut into 20 squares.