Preheat oven to 375 degrees Fahrenheit and butter baking dish (one 8 inch square or individuals ramekins)Combine the oats, half the nuts, sugar, baking powder, cinnamon, and saltIn a bowl. In another bowl, whisk the milk egg, half the butter and vanilla.Arrange bananas in a single layer on the bottom of the baking dish, sprinkle with 2/3 berries then cover with the oat mixture.
Slowly drizzle milk mixture over the oats. Tap dish to distribute liquidScatter remaining berries and nuts across the top
Bake for 35-40 minutes until the top is nicely golden and the oat mixture has set.
Let cool slightly. Drizzle with remaining melted butter and maple syrup.