Step 1: Break the chocolate into pieces and place in a large pan with butter and the condensed milk.
Step 2: Heat gently, stirring continuously, until the buttuer and chocolate melts and becomes smooth. DO NOT ALLOW TO BOIL.
Step 3: Remove from heat and add vanilla essence.
Step 4: Beat the mixture, until your arm begins to hurt (roughly 3-5 mins)
Step 5: Lightly grease a baking tin, then pour the mixture in and smooth the top.
Step 6: Refriderate for a few hours.Then cut into squares. And enjoy!