Put Unsalted Butter (1/2 cup) in a bowl & into the freezer to chill before you begin to prepare your other ingredients.
Blend Gum-Free Gluten-Free Flour (152 gram), Arrowroot Starch (1 tablespoon), Non-Fat Dry Milk Powder (20 gram), Fine Salt (1/4 teaspoon), and Xanthan Gum (1/4 teaspoon) in a bowl with a whisk
Scoop some flour onto a cutting/pastry board, add chilled butter to flour, then add more flour on top of butter.
With a rolling pin, roll the butter cubes until they are all flat, distributing flour on top as necessary.
Gather flour and butter together with a gentle touch & scrape into a bowl, place in the freezer to chill for 5 minutes.
Combine Water (25 gram), Sour Cream (30 gram), and Rice Vinegar (2 teaspoon) together in a small bowl.
Remove the flour and butter bowl from the freezer.
Cut the butter into the flour until butter flakes are smaller in size.
Drizzle 1/2 of the liquid (ice water, sour cream and vinegar) over flour and butter mixture and gently mix together with a fork. Drizzle the other 1/2 of the liquid and continue gently incorporating.
Gather and press the contents together into a loose ball.
Refrigerate dough for 1 hour.
After 1 hour has passed remove dough from refrigerator and let rest at room temperature for 10 minutes.
Prepare two squares of unbleached parchment paper to roll your crust in between.
Place dough in between two sheets of parchment and using a rolling pin, gently begin to roll dough into a disc, alternating directions of the rolling pin.
Occasionally remove the top parchment and coax the edges into a uniform circle as necessary.
Once the dough is a uniform thickness, about 11 inches in diameter, remove top parchment paper and place the dough over your 9inch pie plate, raw dough side down.
Shape the edges of your pie crust and place the pie crust into the freezer to chill.
Preheat oven to 375 degrees F (190 degrees C).
Once the oven is preheated, remove pie crust from the freezer and prick the bottom of the crust all over with a fork.
Place a round piece of parchment in the bottom of your crust and fill with pie weights (dried beans work well).
Brush pie crust edge with a bit of Heavy Cream (1 tablespoon).
Place pie crust in the oven and bake for 15 minutes.
After 15 minutes, remove the parchment and pie weights, and continue to bake for another 5-7 minutes until lightly golden brown around the edges.
Let cool at room temperature. Once cooled, pie crust is ready to be filled and enjoyed!