Firstly, preheat your fan oven to 170 degrees and lightly grease an 8x8-inch baking tray.
Mix the ground flaxseed and warm water in a bowl and leave it to stand until it forms a gel-like consistency.
Keep around half a cup of the nuts and coconut flakes aside for later. In a large, mix the oats, walnuts, almonds, and the baking powder, cinnamon and sea salt.
To the bowl with flaxseed gel, add the soya milk, maple syrup or apple puree and vanilla extract. Whisk thoroughly.
Pour the contents of the bowl with wet ingredients into the dry ingredients and stir to combine. Add in half of the raspberries and half a cup of blueberries.
Add the mixture to the baking tray and top with slices of banana, blueberries and the 1/2 cup of nuts and coconut flakes you kept aside. You can also sprinkle hemp seeds or cacao nibs on top too.
Bake for 45-55 minutes. The top should be crispy but not overly brown and the middle nick and thick. Cool for 15 minutes before serving with a dollop of coconut or soya yoghurt and extra fresh berries and fruit.