Peel the bananas and slice them diagonally into 1/2-inch thick pieces.

In a mixing bowl, whisk together the flour, baking powder, salt, and cinnamon.

In another bowl, combine the milk, egg, and vanilla extract. Mix well.

Gradually add the wet ingredients to the dry ingredients, stirring until just combined. The batter should be smooth but thick.

Heat about 1 inch of vegetable oil in a deep skillet or frying pan over medium heat until hot (around 350°F).

Dip each banana slice into the batter, ensuring it is fully coated, then carefully place it in the hot oil.

Fry the banana slices in batches for about 2-3 minutes on each side, or until golden brown and crispy.

Remove the fried bananas with a slotted spoon and place them on a paper towel-lined plate to drain excess oil.

Dust with powdered sugar if desired and serve warm.