In a small bowl, mix the ground flaxseed with water. Let it sit for 5 minutes to thicken.
In a blender, combine the banana, spinach, plant-based milk, and vanilla extract until smooth.
Whisk together oat flour, all-purpose flour, baking powder, cinnamon, and salt in a large mixing bowl.
Pour the blended spinach mixture and flax egg into the bowl with the dry ingredients. Stir until just combined. If the batter is too thick, add a splash of plant-based milk.
Heat a non-stick skillet or griddle over medium heat. Lightly grease with coconut oil or cooking spray. Pour ¼ cup of batter for each pancake onto the skillet. Cook until bubbles form on the surface, then flip and cook for another 1-2 minutes on the other side.
Top your pancakes with your favorite toppings, such as sliced bananas, fresh berries, a drizzle of maple syrup, or nut butter.