Unfortunately I'm on my phone and can't get the picture recipe to upload but I'll type out the steps for you.
1/4 cup Flour
1/4 cup Sugar
2 Tablespoons Cocoa Powder
Pinch or Salt.
2 Tablespoons oil (Replace with Canna-oil)
3 Tableapoons water
Add dry ingredients into a large coffee mug or microwave safe dish
Add wet ingredients
Mix well until consistency of thick chocolate milk.
Microwave for 1:20-1:40 remember microwaves vary so be carefull.
Here is a link to the recipe it comes with pictures. How to Make Brownie in a Mug