Mash the bananas: In a medium bowl, mash the bananas with a fork until mostly smooth with a few small lumps. You should have about 1 to 1 1/4 cups of mashed banana.

Whisk the wet ingredients: Add the egg and vanilla to the bananas. Stir until combined.

Combine the dry ingredients: In a separate bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and cinnamon.

Make the batter: Add the dry mixture to the banana mixture. Pour in 1/3 cup milk and stir gently. If the batter looks too thick (like heavy muffin batter), add a splash more milk. You want a thick, spoonable batter that drops off a spoon slowly.

Heat the oil: Pour 1 to 1.5 inches of oil into a heavy skillet or pot. Heat over medium to medium-high until it reaches 350–360°F (175–182°C). If you don’t have a thermometer, drop in a tiny bit of batter—if it sizzles and rises to the top within 2–3 seconds, you’re good.

Fry in batches: Using two spoons or a small cookie scoop, drop heaping tablespoons of batter into the hot oil. Don’t crowd the pan. Fry for 2–3 minutes per side until deep golden brown.

Drain and dust: Transfer fritters to a wire rack or paper-towel-lined plate. While warm, dust generously with powdered sugar or toss lightly in granulated sugar.

Serve warm: These are best within minutes of frying. Add a second dusting of sugar right before serving if needed.