Prepare a 9x9 inch cake tin by lining it with a grease proof paper or aluminum foil in such a way that it has a overhang. The overhang will help you pull out the fudge once it has cooled down.
Prepare a double boiler.
Put the butter and chocolate to the bowl.
Keep stirring till the chocolate and butter has turned into a thick sauce that is smooth in texture.
Once the chocolate has melted add the condensed milk, chopped nuts (if using) and vanilla extract.
Mix well.
Transfer the mix to the prepare tin. Even out the surface by tapping the tin a few times and allow it to set.
Cut the fudge into squares of desired size.
Store in the refrigerator.
