01 - Preheat the oven to 350°F. Grease an 8x8-inch baking dish with cooking spray or butter.
02 - In a large bowl, whisk together the mashed bananas, eggs, milk, maple syrup, vanilla extract, and melted butter until well combined and smooth.
03 - In a separate medium bowl, mix the rolled oats, baking powder, cinnamon, nutmeg, and salt until evenly distributed.
04 - Add the dry ingredients to the wet mixture and stir until just combined. Do not overmix.
05 - Pour the batter into the prepared baking dish and spread evenly with a spatula.
06 - Bake for 30–35 minutes, or until the oatmeal is set and golden brown at the edges.
07 - Allow to cool for 5–10 minutes before slicing into portions. Top each serving with Greek yogurt, banana slices, nuts (if using), and a drizzle of maple syrup or honey.