This recipe appeared in the Jan 11, 09 Chicago Tribune.
This makes a delicious brownie for one in about a minute.

Microwave Chocolate Mug Brownie

2 Tbs vegetable oil
2 Tbs water
1/4 tsp vanilla extract
dash salt
4 Tbs granulated sugar
2 Tbs unsweetened cocoa powder
4 Tbs all purpose flour

In a 12 oz coffee mug, add water, oil and vanilla. Whisk well.
Add cocoa powder, whisk well. Add sugar, whisk well. Add flour, whisk
well.

Microwave for 60 to 90 seconds. Center should be slightly molten.
Enjoy with a spoon. Careful brownie will be hot.

I used a 1500 watt microwave. 60 seconds makes a molten center
brownie. 75 seconds make a uniformly done brownie.