Not sure to start with, but tastes lovely.
Ingredients
1 coffee mug
4 Tbsp. cake flour (plain, not self-rising)
4 Tbsp. sugar
2 Tbsp. cocoa
1 egg
3 Tbsp. milk
3 Tbsp. oil
Small splash of vanilla
3 Tbsp. chocolate chips, optional
1 teaspoon peanut butter, optional
Method
1. Add dry ingredients to mug, mix well with a fork.
2. Add egg, mix throughly.
3. Pour in milk, oil and vanilla, mix well.
4. Add chocolate chips if desired. Push a dollop of peanut butter into the center of the batter if desired.
5. Put mug into microwave and cook for three minutes on 1000 watts. Cake will rise over top of mug. Allow to cool for 2 minutes.