In a mixing bowl, whisk together the all-purpose flour, cornstarch, granulated sugar, baking powder, and salt.
Gradually add the cold water to the dry ingredients, whisking until you achieve a smooth batter consistency. The batter should be thick but still pourable.
Peel the bananas and cut them into halves or slices, depending on your preference.Heat vegetable oil in a frying pan or deep fryer to approximately 350°F (180°C).
Dip each banana slice into the batter, ensuring it is fully coated. Allow any excess batter to drip off.Carefully place the coated banana slices into the hot oil, taking care not to overcrowd the pan. Fry them in batches if necessary.
Fry the bananas for 2-3 minutes on each side, or until they turn golden brown and crispy.Using tongs or a slotted spoon, remove the fried bananas from the oil and transfer them to a plate lined with paper towels. This will help absorb any excess oil.
Repeat the frying process with the remaining banana slices.Allow the fried bananas to cool slightly before serving.
Serve the crispy fried bananas on a plate or in a serving dish. You can sprinkle them with powdered sugar or cinnamon for added flavor. For a decadent touch, serve them with a drizzle of chocolate sauce or a scoop of ice cream.