In a microwave-safe mug, combine the flour, sugar, cocoa powder, baking powder, and salt.
Stir the dry ingredients until well mixed.
Add the milk, vegetable oil, and vanilla extract to the mug.
Mix thoroughly until smooth and there are no lumps.
Fold in chocolate chips or nuts if desired.
Microwave the mug on high for 1 minute.
Check the cake; if it’s not fully cooked, microwave for an additional 15-30 seconds.
Let it cool for a minute before enjoying.
Optionally, top with whipped cream or a scoop of ice cream.
Indulge in your warm chocolate mug cake!