Place dry ingredients into a microwave safe mug and stir well.
Add egg and stir.
Add soy milk, apple sauce, vegetable oil, and vanilla and stir.
Add chocolate chips and stir.
Place in microwave and cook for 3 minutes at full power (1000 watts). The batter will rise/inflate while cooking - don't worry - it won't spill over.
Let cool and eat right out of the mug!
NOTE: Original recipe called for all purpose flour, 4 tablespoons of sugar, 3 tablespoons of oil, and a greased mug so the cake can slide out after cooling. To be honest, I found the serving a bit too large, but I'm not accustomed to eating such big servings of dessert!