First, make the graham pie crust. Combine oat flour, buckwheat flour, baking soda, cinnamon, salt, and sugar. Mix well.
Add coconut milk, water, and vanilla bean past. Mix until dough starts to come together.
Scrape sides of bowl and continue mixing until dough is smooth and consistent.
Roll between 2 sheets of parchment paper until it is slightly bigger than the pie mold.
Dust the rolling pin with gluten-free flour before using to pick up and transfer to the pie mold. Lightly brush mold with oil.
Press dough into pie mold evenly, then dock dough with fork. Chill dough for at least 30 minutes before filling and baking.
Next, prepare the squash. Cut the squash in half from end to end and remove the seeds. Place on parchment paper, cut side down, and roast in 325° oven for 45 to 60 minutes, until squash is tender. Remove skin. Measure 4 cups of the roasted squash for the recipe.
Combine all ingredients (except the crust) in a large plastic container. With an immersion blender, blend until completely smooth.
Pour mixture into pre-set pie shell. Bake at 325° for 25 minutes. Rotate pan and continue to bake for 25 to 30 more minutes.
Bake pie until it reaches 175° internal temperature. Let cool at room temperature for 1 hour. Then, serve and enjoy!