Directions:

Mix flour, sugar, baking powder, salt, milk butter and vanilla in a mug.
Add blueberries and gently fold into the cake batter being careful not to crush them.
Place mug in microwave for one minute. Check to see if it has a cake-like texture. If not, microwave for an additional ten seconds.
Allow to cool for one minute.
If desired, add a scoop of ice cream or whipped topping.
Enjoy!