These are all the ingredients. Make sure you grease the mug up with some spray so it doesn't stick to the mug.
1/4 cup of flour
Depending on how much sugar you want. If you are watching your sugar intake, I would go with 1/8. If you just want a sweet brownie, you can do 1/4 cup.
Try 1:10 seconds and if you like a kind of softer brownie.