Combine all coating batter ingredients in a mixing bowl.
Peel bananas and cut each into two. Make three slices along its length, but keep the bottom 1 inch intact, so it can be opened up like a fan.
Heat enough oil in a pot for deep frying.
Dip the bananas into the batter then roll on oat to fully coat the banana. Fry until golden brown and crispy, about 3-4 minutes. Remove and drain on paper towel or wire rack. Serve immediately.