In a medium bowl, combine the brown rice flour, buckwheat flour, baking powder, cinnamon, and salt. Stir well.
In a large bowl, mash the banana. Stir in the egg, melted butter, sugar, and vanilla. Whisk in the milk. Add the flour mixture and stir until well-combined and there are no lumps. Stir in the chocolate chips if using.
Heat a griddle to 375 degrees F or large skillet over medium-low heat. Coat with nonstick cooking spray, if needed (if you have the Presto Griddle mentioned above, you probably won't need it!). For each pancake pour about 1/4 cup of batter onto griddle. Flip when they start to bubble. Cook until golden brown. Repeat with remaining batches, spraying the griddle or skillet if needed.