Creating Baked Oats is simple if you follow these easy steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C) and grease a baking dish.
2. Mix Dry Ingredients: In a large bowl, combine the rolled oats, baking powder, cinnamon, and salt.
3. Combine Wet Ingredients: In another bowl, whisk together the milk, maple syrup, mashed banana, and vanilla extract until well blended.
4. Combine Mixtures: Pour the wet ingredients into the dry mixture and stir until combined.
5. Add Fruits and Nuts: Gently fold in the mixed berries and nuts, ensuring they are evenly distributed.
6. Transfer to Baking Dish: Pour the mixture into the greased baking dish, smoothing it out with a spatula.
7. Bake: Place in the preheated oven and bake for 30-35 minutes or until the top is golden brown and the oats are set.
8. Cool: Remove from the oven and allow to cool for about 5-10 minutes before serving.

These steps will guide you in creating this incredible dish effortlessly.