Steam the bananas with skin on for 15 to 20 minutes. Set aside and let them cool to room temperature before making the dough.
In a large bowl, add in the peeled steamed bananas. Mash them with fork until soft and no more clumps.
Add in half of the flour, corn starch, vanilla, maple syrup, and a pinch of salt. Mix them together with a spatula until well-incorporated. Here you can add more flour if your mixture is still moist. Mix everything until the dough shapeable.
To shape the dough, grease your hands with a little bit of oil to avoid the dough from sticking and take about a table spoon of the dough. Flatten the dough on the tip of your fingers and fill it with chocolate chunks. You can be generous here as long as you can still cover the chocolate fully. Wrap the chocolate around and shape it into a ball. Repeat to make all the balls.
Pre-heat the oil over medium-low heat while preparing for the coating.
In a small bowl, mix in the flour and water to create the slurry. The consistency should be slightly thicker but not so thick. Just enough to coat the balls evenly.
In a medium bowl, add in panko bread crumbs.
Take a ball, dip it in the slurry until all covered and then directly coat it in the panko bread crumbs. Make sure it's covered properly by gently pressing the panko and shape it again into ball to keep it in shape before frying.
Deep fry over medium-low heat until golden brown. Do now crowd the frying pan so all the balls cook evenly and beautifully. Serve and enjoy!