Ingredients

3 tablespoons all-purpose flour
3 tablespoons sugar 
2 tablespoons cocoa powder 
1/4 teaspoon baking powder 
Pinch of salt, optional 
3 tablespoons milk 
3 tablespoons vegetable oil 
Splash vanilla extract, optional 
3 tablespoons chocolate chips 

Directions

Step 1
Special equipment: a 12-ounce microwave-safe ceramic mug and a microwave oven

Step 2
Put the flour, sugar, cocoa powder, baking powder and salt if using in a 12-ounce microwave-safe ceramic mug. Blend thoroughly with a fork. Add the milk, vegetable oil and vanilla if using and blend until smooth. Stir in the chocolate chips.

Step 3
Microwave on high for 90 seconds. Do not overcook or the cake will be dry. Let cool for 2 to 3 minutes before eating.