Preheat the oven to 350°F.
Chop the apples and transfer to a large bowl of water with a squeeze of lemon (this prevents browning).
In a small bowl, mix together the ground flaxseed and water. Set aside for 5 minutes to thicken.
In a large bowl, mix the rolled oats, nuts, raisins, baking powder, cinnamon, nutmeg, chia seeds, hemp seeds, and salt.
In a separate bowl or glass measuring cup, mix together the almond milk, maple syrup, and vanilla. Add the thickened flax mixture.
Add the wet ingredients to the dry ingredients and mix well using a spatula.
Drain the apples well in a colander and stir into the oat mix. The mixture will seem loose – this is ok.
Transfer the mix to an 9x9 inch casserole dish (or similar size). Cover with tinfoil and bake for 50 minutes.
After 50 minutes remove the tinfoil, sprinkle the coconut sugar (if using) on top and continue to bake for another 20 minutes.
Remove from the oven and let sit for at least 10 minutes. Slice or spoon out and serve! Top with Almond Caramel from The Plant-Based Cookbook, nut butters, maple syrup, additional nuts and/or fresh berries.