In a large mixing bowl, combine the mashed bananas, sugar, and vanilla extract.
In a separate bowl, mix the flour, baking powder, ground cinnamon (if using), and salt.
Gradually add the dry ingredients to the banana mixture, alternating with water or milk, and stir until you get a thick, smooth batter. You may not need all the water or milk.
In a deep skillet or frying pan, heat the vegetable oil over medium heat until hot but not smoking.
Drop spoonfuls of the batter into the hot oil, being careful not to overcrowd the pan.
Fry the fritters for about 2-3 minutes on each side, or until they are golden brown and cooked through.
Use a slotted spoon to remove the fritters from the oil and drain them on paper towels.
Enjoy your meal!