Add the wet ingredients to the same bowl as the dry ingredients.
In a separate bowl, mash the two bananas into a paste.
After the bananas are thoroughly mashed, add to the bowl with the liquid and dry ingredients. Whisk until thoroughly mixed and the batter looks smooth.( In the beginning the batter will look like quite doughy but continue whisking and it should liquidize.)
Add in the blueberries with your hands to make sure they're distrubeted evenly.
Line a cupcake tin, and fill each liner about 2/3 of the way.
Top with a few blueberries (this is optional. Because the batter is so thick, the blueberries on the top do not sink down and I think it looks pretty xD).