Place the rolled oats into a high-speed blender and pulse until they reach a fine, flour-like consistency.
Add the egg whites, Greek yogurt, half a banana, cinnamon, baking powder, vanilla extract, and sea salt to the blender.
Process the mixture on high until the batter is completely smooth and well-combined.
Heat a large non-stick skillet over medium-low heat and lightly coat the surface with the coconut oil.
Pour 1/4 cup portions of the batter onto the hot skillet, ensuring there is enough space between cakes for flipping.
Cook for 3-4 minutes until small bubbles form on the surface and the edges appear set and dry.
Carefully flip each griddle cake and cook for an additional 1-2 minutes until the centers are firm and the outsides are golden brown.
Serve immediately while warm, optionally garnished with fresh fruit or a dollop of extra yogurt.