Put the sweet rice flour, sorghum flour, corn flour and potato starch in a large bowl and whisk to combine. Add the xanthan gum, guar gum and salt.
Cube the butter and leaf lard into 1-inch pieces. Lay them gently on the flours. Put the bowl in the freezer for 15 minutes.
Working quickly, take the bowl out of the freezer. Using a pastry blender or your hands, work the butter and leaf lard into the flours, coating the fat, until the butter and leaf lard are the size of peas. Don't go too far. You still want to see the fats in the flours.
Pour 3 ounces cold water onto the mixture. Stir gently with your hands. You are looking for the flours and fats to be just wet enough that they stick together when pinched. You might need to add an additional tablespoon or two water, depending on the day. If you add a bit too much water, that's okay. A wet dough is better than a dry dough.
Bring the dough together into a ball. Gently flatten it into a disc. Wrap it in plastic wrap.
Refrigerate the dough for at least 1 hour.
Place the disc of dough between two pieces of plastic wrap (you can also use wax paper or parchment paper). Working from the center outward, gently roll out the dough into a 10-inch circle.
Remove the top layer of plastic wrap and gently fit the pie dough into a 9-inch pie pan. Settle it in gently. Don't stretch or push it around too much. Remove the second piece of plastic wrap. If the dough breaks, take small pieces of the dough and fill in any holes, smoothing the dough with slightly moistened fingers. Crimp the edges.
Put the pie pan in the refrigerator for at least 30 minutes.
Preheat the oven to 400 degrees F.
Place a buttered piece of foil on the pie dough, nestling it gently against the sides. Fill the foil with dried beans or pie weights.
Bake the pie dough for about 20 minutes. Remove the beans and aluminum foil and return the pie dough to the oven for an additional 8 minutes.
You now have a blind-baked pie crust, ready to finish with pumpkin filling.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.