In a medium-size mixing bowl or measuring cup with a pour spout, place the ground oats (or substitute), baking powder, and salt. Whisk to combine well.
Add the beaten eggs and mashed banana, and whisk until uniform in texture. For a smoother batter, blend briefly with an immersion blender.
If the batter seems especially thin, let it sit for about 5 minutes to allow it to thicken.
Heat a griddle to 325°F or place a nonstick, heavy-bottom skillet over medium heat until hot. Grease the hot surface with a bit of the (optional) butter.
Whisk the pancake batter once more to ensure uniformity, and pour it onto the hot, greased skillet in scant 1/4-cup portions.
Allow the pancakes to cook, undisturbed, for about 3 minutes or until golden brown on the underside. They won't bubble up much on the uncooked side even as they cook through.
Flip the pancakes and allow to cook for only about 1 minute more, or until set. Remove from the skillet or griddle and repeat with any remaining batter. Serve immediately, or keep warm in a 200°F toaster oven until ready to serve.
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Notes
For the oat flour.If you need or want to replace the oats, this recipe also works with 1/3 cup (40 g) blanched almond flour (not almond meal).You can also try using quinoa flakes, ground into as fine a powder as possible, which typically work as a substitute for oat flour.Nutritional information.Nutrition information is an estimate, per pancake, from online nutrition calculators. It is not to be relied upon.