In a medium bowl, mash the banana with a fork until mostly smooth.
Stir in the sugar, vanilla extract, and cinnamon.
Add the flour, baking powder, and salt. Mix until just combined.
Stir in the milk to create a thick batter.
Heat about 1/2 inch of vegetable oil in a skillet over medium heat.
Drop heaping spoonfuls of batter into the hot oil, cooking 1–2 minutes per side until golden brown.
Remove fritters and place on a paper towel–lined plate to drain excess oil.
Serve warm with a dusting of powdered sugar or a drizzle of honey, if you like.