Combine flour, baking powder, and salt in a bowl. Mash bananas, sugar, vanilla extract, and cinnamon together in a separate bowl. Stir flour mixture into banana mixture until batter is well mixed.

Pour 2 inches of oil into a heavy pot and heat over medium heat.

Working in batches, drop batter by the tablespoon into hot oil; cook until lightly golden brown, 2 to 3 minutes per side. Transfer banana balls to a paper towel-lined plate to drain and cool slightly. Dust banana balls with confectioners’ sugar.