Preheat the oven to 350 degrees.
Mix all the crust ingredients in a large bowl then transfer them to pie pan. Wet your hands lightly to prevent the crust from sticking to them then press the crust into the pan, making sure it is even on the sides and bottom. Bake for 10 minutes.
Bring a medium sized pot of water to a boil. Add the purple yams (cut into small cubes) and boil for 10 minutes, or until the yams can be pierced with a fork. Drain the yams then put them in a high-powered blender or food processor.
Add the rest of the pie filling ingredients and blend until everything is smooth. Pour the pie filling into the baked pie shell and smooth out the top. Bake for 45 minutes, or until the pie has set but still has some jiggle in the middle. Remove the pie from the oven and let it cool completely before serving it.