Quick&Easy BROWNIE recipe IMPROVED (mug size)

When my friends are coming over they always want a specific thing: my improved brownie recipe (in A MUG, of course)
I tried various recipes, but this is the best one!

What you'll need:
*1 egg
*4 1/2 tb of sugar
*2 tb of oil (I use sunflower oil)
*1 1/2 tb of flour (I like to sift it before it goes into the mixture)
*2 1/2 tb of cocoa powder (you can use simple cocoa powder or Nesquick)
*a mug (preferable, a heat resistant)
optional: a tiny drop of vanilla essence

Instructions:
Crack your egg , put in the mug and then whisk it up.Mix all the other ingredients: oil, flour, sugar, cocoa powder and optional, a tiny drop of vanilla essence.After you mixed up everything, place your mug in the microwave for 1 minute and 40 seconds (it depends very much likely on your microwave). You can check with a toothpick if the mixture is done.

Let it sit for about 1 or 2 minutes.You can serve it with:
*Sifted sugar powder
*Nutella
*Ice cream
*Raspberries, Strawberries, Blueberries

Enjoy your cup brownie. It's really, but really delicious.