1/4 cup flour
1/4 cup sugar
1/4 teaspoon salt
2 tablespoons cocoa, unsweetened
2 tablespoons egg, whisked
3 tablespoons milk
3 tablespoons oil
3 tablespoons chocolate chips or crushed candy bar (optional)
1/4 teaspoon vanilla extract

Mix first four ingredients together in large coffee mug; add egg and mix until paste forms.
Stir in milk and oil, then chocolate chips and vanilla.
Microwave on medium for 3 minutes, until cake starts to crown over top of mug.

(I mix everything together in a bowl, put it in a mug and nuke it. )