Cookie in a Mug

I've a chocolate chip cookie in a mug a few times over the last week, as I made one for myself then a couple of my flatmates asked me to make one for them! Its really simple and only takes about 4-5 minutes. The recipe is from the blog number 2 pencil. The popularity of the cookie has made me decide to make more 'in a mug' recipes in the next few weeks, so keep an eye out for those!