Preheat oven to 375 degrees Fahrenheit and position rack in the middle of the oven. Spray a 9- or 10-inch pie pan with baking spray or oil the pan with coconut oil or vegan butter.
Add the coconut milk, pumpkin, eggs, sugar, and vanilla to the pitcher of a blender. Blend until combined, about 20 seconds. Add the flour, baking powder, pumpkin pie spice, and salt. Blend again until well-combined, another 20 seconds.
Pour filling into the pie plate. The mixture will be fairly runny. Carefully transfer to the preheated oven.
Bake until the middle just barely jiggles, 40-50 minutes. I like to check the middle by giving the pie pan a little nudge, and if it seems like it's no longer liquid, I'll pull the pie out and insert a butter knife about halfway between the center and the edge. If the knife comes out relatively clean - no runny pie filling - it's done!
Place on a cooling rack and let cool, about 1 hour. Transfer to refrigerator to completely cool, at least one more hour (or up to 3 days in advance).
If desired, top pie with dollops of coconut whipped cream. Or simply cut slices, transfer to a plate, and top individual servings with the whipped cream.
Keeps in the refrigerator for 3-4 days. I suggest covering the completely cooled pie with plastic wrap if not serving right away.
* I have tested this pie recipe with only one gluten-free flour blend, and it turned out great! I used Pamela's Gluten-Free Artisan Flour Blend.** To make coconut whipped cream, refrigerate 1-2 cans of full-fat coconut milk. Skim the coconut cream off the top and place in a bowl. Whip with a hand mixer until the consistency of whipped cream. Add a bit of powdered sugar or pure maple syrup to sweeten, to taste, and/or a bit of vanilla extract if desired.
To freeze, let cool completely then wrap well in plastic wrap and transfer to freezer. To thaw, transfer to refrigerator 24-48 hours before serving or let sit at room temperature for 2-3 hours.Adapted from LA Times via Cookistry.