Stir together the flour, flaxseed, baking powder, cinnamon, and salt in a medium bowl.
Stir in the banana, milk, oil, and vanilla. Gently combine to make a uniform, thick batter.
Heat a cast-iron or nonstick skillet or griddle over medium heat. Coat with neutral oil. Spoon out ΒΌ cup of the batter at a time, or less to make smaller pancakes, and spread to an even thickness about 1/2 inch thick. (Add a few slices of banana on top of each if desired.) Let cook about 3 minutes or until the edges are set.
Carefully flip and cook for another 1-2 minutes.
Serve immediately and repeat with the rest of the batter.
Serve with maple syrup, sliced banana, or other desired topping.