Preheat the Oven: Set your oven to 190°C/375°F/Gas 5.

Prepare Flax Eggs: In a small bowl, combine 2 tablespoons of ground flaxseed with 6 tablespoons of water. Stir well and set aside for about 15 minutes to thicken.

Combine Wet Ingredients: In a large mixing bowl, add mashed bananas, almond milk, nut butter, shredded coconut, chocolate chips, crushed walnuts, flax eggs, maple syrup, vanilla extract, and salt. Whisk everything together until well combined.

Incorporate Dry Ingredients: To the same bowl, add rolled oats and baking powder. Mix until all ingredients are evenly incorporated.

Prepare Baking Dish: Lightly grease a square baking dish with coconut oil or non-stick spray.

Pour Batter and Add Toppings: Pour the oatmeal batter into the prepared baking dish. Optionally, top with additional chocolate chips, coconut flakes, or crushed walnuts for added flavor and texture.

Bake: Place the baking dish in the preheated oven and bake for about 35 minutes, or until the oatmeal is set and lightly golden on top.

Cool and Serve: Once baked, remove the oatmeal from the oven and allow it to cool before slicing into portions. Serve warm or store leftovers in an airtight container in the refrigerator for later consumption.