Preheat the oven to 350°F. Lightly grease an 8 1/2 or 9-inch pie tin/dish with coconut oil and set aside.
In a blender or food processor, grind the buckwheat groats until they have a "cracked" appearance, or at least until most of the grains are visibly split in half. Dump the ground buckwheat groats into a large bowl.
To the buckwheat, add the baking powder, ground flaxseed, vanilla powder, cinnamon, nutmeg, ground ginger, and sea salt. Stir lightly to combine.
In a medium bowl, whisk together the coconut milk and maple syrup.
Start layering: Pour a third of the coconut milk mixture in the greased pie dish. Then, evenly sprinkle half of the buckwheat mixture on top of the milk. Sprinkle half of the walnuts and diced apples on top of the buckwheat. Grate some more nutmeg or sprinkle additional cinnamon here if you like. Pour another third of the coconut milk on top next. Then, add the other half of the buckwheat mixture. Pour the remaining coconut milk on top and garnish with remaining walnuts and diced apples.
Give the pan a good shimmy-shake and some light taps on the counter. A few air bubbles should poke through. It's going to look like a hot, soggy mess at this point. Drizzle the melted coconut oil on top and slide the dish into the oven. Bake for 45-50 minutes or until the top is golden and everything is set. Serve the hearty apple-spice baked buckwheat warm with extra maple syrup and coconut yogurt.
Recipe Notes
I ground the buckwheat in the dry container of my Vitamix, but I think a food processor might be better. You kind of want the grains to have a "cracked" appearance. Definitely avoid over-processing them into flour-like bits.
Apple spice baked buckwheat is a naturally gluten-free and cozy baked breakfast porridge option. Warming, filling, and delicious!