Prepare a 9-inch pie pan by greasing it with butter or nonstick baking spray and generously coating it with Gluten-Free Flour Mix (recipe below).
Mix flours, sugar, xanthan gum and salt in a bowl. Using a pastry cutter or fork, cut cold butter into dry ingredients until it becomes crumbly and resembles small peas. Add egg and orange juice, and mix with a fork until the dough combines. Form into a ball and place in the refrigerator, covered with wax paper, for 10 minutes.
Lay down a sheet of wax paper and place the ball of dough in the middle. Lay another piece of wax paper over the top and press down gently with your hands to flatten the ball. Roll the dough with a rolling pin until it is about 1/4-inch thick, making sure to keep an even thickness and fill in any cracks with dough from the edges.
Remove the top sheet of wax paper and place the dough in the pan, then peel off the remaining sheet of wax paper and gently press the dough into the pan. Take care not to puncture the dough with your fingers or fingernails. Crimp the edges and prick a few holes in the bottom of the dough with a fork. Cover pie pan loosely with wax paper and place in freezer for 15 minutes.
While the dough is freezing, place rack in the middle of the oven and preheat oven to 350 degrees.
Remove pie pan from freezer and line crust with aluminum foil, making sure to seal the edges so they don’t burn. Bake for 10 minutes, then remove foil and bake for another 10 minutes, or until crust is a pale brown. Remove from oven and set aside.
For the filling:
Preheat to 425°F (218°C). Cut squash in half lengthwise and scoop out seeds with a spoon. Lay squash face down on a jelly-roll pan and pour 1/2 cup of water into the pan. Roast in oven for 1 hour, checking occasionally to make sure there is still water in the pan. Squash is done when a fork easily penetrates the flesh. Remove squash from oven, allow to cool and scoop flesh out with a spoon. You need 1 1/2 cups of mashed squash for the filling.
Make a shield for the edge of the pie crust by cutting 3-inch-thick strips of foil and folding them over the edges of your crust to protect them from burning. The foil should not dip down into the basin of the pan. Make sure it just covers the crimped parts around the rim of the pie pan.
To make the filling, combine all ingredients in a blender or food processor. Blend on high for 1 minute, or until ingredients are liquefied. Pour filling into pie crust and carefully place on the center rack of the oven. Bake for 45 minutes, or until a toothpick inserted in the pie comes out clean.
Place pie on wire rack until completely cooled. Slice and serve with whipped cream, which is nice with a little cayenne pepper.
Variation: For standard pumpkin pie, replace the butternut squash with 1 1/2 cups of fresh, unseasoned pumpkin puree. If you are roasting your own pumpkin, cut open the top, scoop out the seeds and split the body into four pieces. Roast according to directions above.
Nutritional analysis is based on using Bob's Red Mill G-F Baking Flour, it is used only for nutritional calculations.