there is also a mug size version:

5 tbsp all purpose flour

4.5ctbsp sugar/sweetener

2 tsp unsweetened cocoa powder

1/4 tsp baking soda

pinch of salt

1/2 tsp vinegar

1/4 tsp cooking oil

4 1/2 tbsp water

mix dry ingredients in large mug

make 3 depressions in dry ingredients

Pour each liquid in each depression

Pour water over all dry ingredients and mix well with fork until well mixed and smooth

Put in microwave for 2 minutes on high or until done. put fork or knife in the middle.