• Preheat the oven to 350ºF / 180ºC and grease and line a 9 inch square baking tin
• Place the butter and flour and sugar for the cookie base into a food processor and pulse until you see the mixture resemble fine crumbs. Continue pulsing until the dough starts to stick together then tip into the base of the baking tin.
  
• Press into an even layer, I use the back of a measuring cup to do this. Prick all over with a fork then bake for 15 to 20 minutes until starting to turn a pale golden brown.
  
• Remove from the oven and allow to cool completely.

Now make the caramel:

• Place the condensed milk, butter and brown sugar into a saucepan and heat over a medium heat stirring continually. Allow to come to a gentle boil then reduce the heat to low and continue to heat and stir until the caramel turns light golden and starts to pull away from the sides of the pan. This should take around 10 to 12 minutes.
  
• Pour over the cooled cookie base.
  
• Place in the fridge to chill for at least one hour.
• Melt the chocolate and pour over the top of the chilled caramel then place back in the fridge to harden the chocolate for around 15 to 30 minutes
  
• Slice and serve.
  
• If you want to store leftovers, place between parchment paper and store in the fridge for up to one week.