Preheat the oven to 350 F.
Poke a few holes into the sweet potato and put it in the oven. It will roast for about 1 hour until soft.
In a food processor, mix the egg and lard together, then add the coconut sugar and mix again, scraping down then sides if needed. Add the flours, salt, and baking soda and then mix again.
At this point, remove the lid of the food processor and feel the dough. If it’s super sticky you’ll need to keep adding 1 tbs of Tapioca flour at a time and then mixing until you can touch the dough and feel like you could spread it in a pan without it getting stuck to your fingers. It usually takes me about 3-4 tbsp to get there, but this depends on the size of the egg you used, etc.
Transfer the dough to your pie pan and using your fingers, press the dough evenly all around the bottom and up the sides of the pan. If the dough sticks to your hands, wet them slightly. Refrigerate for 15 minutes.
After the refrigeration time is up, poke holes all over the bottom of the pie crust with a fork. (Option: put pie weights in bottom of pan to prevent crust from puffing up). Then bake in the oven (don’t worry that your sweet potato is in there) for 20 minutes.
Once your potato is done, turn the oven down to 325 F and then let the potato cool until you can comfortably touch it. Peel it, and then puree it in a blender, food processor, or using an immersion blender. This will make the consistency of the pie nice and smooth. Measure out 1.5 cups of puree.
In a large bowl, whisk together the eggs, maple syrup, salt, cinnamon, ginger, and vanilla extract, then add the sweet potato puree and coconut milk to the mixture and whisk until combined.
Pour the mixture into the pie shell and bake for 1 hour or until the filling is set. You may need to put a pie crust shield or a piece of aluminum over the crust halfway through to help prevent the crust from turning too brown. Let cool completely before serving.