In a microwave-safe mug, combine flour, sugar, baking powder, and salt.
Add milk, vegetable oil, and vanilla extract to the dry ingredients.
Mix thoroughly until smooth, ensuring no lumps remain.
Microwave on high for 1 minute. Check for doneness.
If not cooked through, microwave in 10-second intervals.
Let the cake cool for a minute before serving.
Top with whipped cream or frosting if desired.
Enjoy directly from the mug or transfer to a plate.
For added flavor, consider mixing in chocolate chips or nuts.
Store any leftovers in the fridge for later enjoyment.