Preheat the oven to 350°F (180°C) and grease a baking dish.
In a large bowl, mix together the mashed bananas, rolled oats, milk, maple syrup, chia seeds, flaxseeds, sunflower seeds, pumpkin seeds, cinnamon, salt, and vanilla extract.
Pour the mixture into the prepared baking dish and spread it evenly.
Bake for 30-35 minutes or until the top is golden brown and the oatmeal is set.
Serve warm with pouring cream or coconut cream, or enjoy cold as a grab-and-go breakfast option.
