Make the oat 'flour' and batter base: Place 1 cup rolled oats in a blender or food processor and pulse until they reach a coarse–fine flour (15–30 seconds). This creates a smoother pancake texture than leaving whole oats while still keeping the oat flavor and fiber. If you don't have a blender, use quick oats and whisk vigorously.

Combine wet and dry: Add the mashed ripe banana, 1 cup milk, 1 tsp vanilla extract, 1/8 tsp salt, and 1/2 tsp cinnamon (if using) to the oat flour. Blend or whisk until just combined and mostly smooth — a few small oat flecks are fine. The mashed banana replaces eggs as a binder and adds natural sweetness; blending distributes it so pancakes rise evenly.

Add lift: Stir 1 tsp baking powder into the batter and let it rest 5 minutes. Baking powder gives the pancakes a light, tender crumb; the brief rest hydrates the oats so the batter thickens slightly and holds air.

Prep the berries: If using large strawberries, quarter them; leave blueberries whole. Pat any wet berries dry with paper towel so they don’t water down the batter or cause steam pockets during cooking. Toss half the berries gently into the batter (reserve the rest for topping). Folding some into the batter ensures berry flavor inside each pancake without bursting every one.

Preheat the pan: Warm a nonstick or well-seasoned cast-iron skillet over medium heat for 2–3 minutes. Test with a drop of water — it should dance and evaporate. A properly preheated pan gives you an immediate sizzle that creates a golden crust; too cool and the pancakes will be pale and dense.

Cook the pancakes: Add 1 tbsp butter or oil to the pan and swirl to coat. Pour 1/4-cup rounds of batter onto the skillet (you should get about 6 pancakes). Cook 2–3 minutes until bubbles appear across the surface and the edges look set; this is the batter releasing steam and setting the structure. Gently flip and cook 1½–2 minutes more until deep golden. Lowering the heat slightly if they brown too fast prevents raw centers.

Finish and keep warm: Transfer finished pancakes to a baking sheet in a single layer and keep them in a very low oven (200°F/95°C) while you cook the rest so they stay warm and the crust stays crisp. Avoid stacking wet pancakes or they’ll steam and become soggy.

Warm the maple syrup and berries: In the same skillet over low heat, add the reserved berries and 1 tbsp maple syrup; cook 1–2 minutes until berries release a little juice and syrup is warmed — this makes a glossy, slightly sauced topping that contrasts the pancakes' tender crumb.

Plate and serve: Stack 3 pancakes per person (about 6 total for 2). Spoon the warmed maple-berry compote over the stack and drizzle with the remaining maple syrup if desired. Finish with a small pat of butter (optional) or a few fresh berries for color. Serve immediately so the exterior stays crisp and the interior tender.