I've tried making fudge before with mixed results mainly because I was guessing the temp and my pan probably wasn't up to the task so I decided to invest in a thermometer and a good sized, non stick pan.
Recipe: (This will make about 1.5lbs of fudge)
450g / 1lb Caster Sugar
300ml / 1/2pt Water
397g / 14oz Tin Condensed Milk
115g / 4.5oz Plain Cooking Chocolate (small pieces)
So put the sugar and water in a large heavy based pan
and on a low heat allow the sugar to dissolve before turning up the heat to bring to the boil. Make sure you put the thermometer in the pan when the liquid is cool so not to damage it.
Remove the pan from the heat and with a wooden spoon mix in the chocolate until smooth. If you've got the temp correct you'll have time to do this before the 'drying' effect occurs. Pour into prepared non stick tin (I used a sillicone 'tin').