Microwave fudge

I made this on a whim over the weekend, after a friend posted about fudge on Facebook. Quick, easy but super messy if you don't watch it like a hawk!

Ingredients:
1 tin condensed milk
500 grams castor sugar
100 grams butter
5 ml vanilla extract

Mix the milk, sugar and butter in an oversized microwave safe bowl. The size is important because it tends to spill over while the sugary mix boils.
Microwave for 3-5 minutes stirring every minute or so until the sugar is dissolved.
Then microwave for another 8-12 minutes while watching it carefully, stir every time the mixture threatens to boil over. In the last few minutes this could be less than a minute apart.
Be super careful not to touch the hot mixture, it reaches incredibly high temperature.
The fudge is done when it turns a golden brown colour.
Pour into a dish lined with baking paper and allow to cool; cut into squares when cooler but not totally set (to avoid the pieces breaking).