Place rolled oats in the blender. Grind to a fine powder. Add banana, sugar (if using), cinnamon and milk. Blend again to make smooth batter.
Meanwhile, heat a pan over medium-high heat. Brush with butter. Pour ¼ cup batter, and spread to form a circle. Place few choc chips on top. Cook for 3-4 minutes or until bubbles appear on surface. Turn and cook for another 2 minutes or until cooked through. Transfer to a plate. Repeat with the remaining batter, and make 6-8 pancakes. Brush pan with butter between batches.
Serve these banana oat pancakes with sliced bananas, honey, maple syrup or ice cream.