Peel the bananas and cut them into 2–3 inch (5–8 cm) diagonal pieces or lengthwise halves, depending on desired presentation. Pat dry with paper towels to remove excess moisture so the batter adheres.

Make the dry mix

In a medium bowl whisk together the all-purpose flour, cornstarch, granulated sugar, baking powder and fine salt until evenly combined.

Mix wet ingredients

In a small bowl beat the egg lightly, then whisk in the milk and vanilla extract (if using) until smooth.

Combine into batter

Make a well in the dry mix and pour in the wet mixture. Stir gently until just combined and no large streaks of flour remain. The batter should be thick enough to coat the bananas—if too thick add 1 tsp milk at a time; if too thin add 1 tsp flour. Batter consistency should be similar to pancake batter but slightly thicker.

Frying & Finishing

Heat oil

Pour about 2–3 cups of neutral oil into a wide, heavy-bottomed skillet or saucepan to a depth of about 1 to 1½ inches (2.5–4 cm). Heat over medium-high heat until the oil reaches 350°F (175°C) or a small drop of batter sizzles and rises immediately but doesn't burn. Maintain temperature around 325–350°F while frying.

Coat and fry bananas

Working in small batches (3–4 pieces depending on pan size), dredge each banana piece in the batter to coat completely, letting excess drip back into the bowl. Carefully lower into hot oil with tongs or a slotted spoon. Fry for 1½–3 minutes per side, turning once, until golden brown and crisp. Adjust time for thicker pieces or plantains (they may need slightly longer).

Drain

Use a slotted spoon to transfer fried bananas to a paper-towel-lined tray or a wire rack set over a sheet pan to drain excess oil. Keep in a warm oven (200°F / 95°C) if frying in multiple batches so earlier batches remain crisp.

Finish and serve

Sift confectioners' sugar and the optional ground cinnamon together and dust over the fried bananas while still warm. Serve immediately with lemon or lime wedges and drizzles of maple syrup or honey if desired.

Safety & tips

Do not overcrowd the pan — crowding lowers oil temperature and yields soggy results. Monitor oil temperature and reduce heat briefly if it starts to smoke. Leftovers can be reheated in a 375°F (190°C) oven for 5–7 minutes to re-crisp.