The pom pom took less than 5 minutes and I think really transformed the hat. I've seen plenty of tutorials on pinterest on how to make a pom pom so I just did it by memory.
Wrap the yarn around your fingers at least 50 times.
Take it off your fingers and tie a long piece of yarn around the middle of the loops. Cut the middle of all the loops when the middle is firmly tied.
Using a large eye needle simply sew into the top of the hat, as many times until it is firmly attached. Then cut the long threads and trim the pom pom ends until you are happy!
I will be wearing the hat more now! Especially when I get back to the UK and it's COLD!