-
In a bowl, cream the butter until soft and fluffy, add in eggs one at a time and then water.
-
Add in cake mix, beat until well combined, fold in half of the blueberries.
-
Pour cake batter into mugs; fill it up to 2/3 full. Top with more blueberries.
-
Place in the microwave in medium-high setting for one minute and thirty seconds.
-
Serve warm.