Preheat the oven to 350°F (175°C). Grease or line 6 jumbo muffin cups with paper liners.
In a large mixing bowl, combine the mashed bananas, granulated sugar, brown sugar, melted butter, egg, and vanilla extract. Mix well until smooth.
In a separate bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, and ground cinnamon.
Gradually add the dry ingredients to the banana mixture. Stir gently until just combined. Do not overmix.
Divide the batter evenly among the 6 jumbo muffin cups, filling each about 3/4 full.
Bake in the preheated oven for 22 to 25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Remove the muffins from the oven and let them cool in the pan for 5 minutes.
Transfer the muffins to a wire rack to cool completely before serving.