I don't remember where I got this recipe but I have used it a couple times and it seems to work ok. I changed a couple ingredients, this is exactly what I used.
1 cup all purpose gluten-free flour (I used Bob's Red Mill)
1 Tbsp sugar
1/2 tsp xanthan gum
1/4 tsp salt
6 Tbsp cold lard
2 tsp lemon juice
mix all dry ingredients & butter until crumbly, then add egg & lemon juice. Mix until it all holds together.
Shape into a ball , put between 2 pieces of wax paper, roll to desired thickness, remove 1 sheet wax paper, flip into pie plate, remove other sheet of wax paper & shape as needed.
It worked fine. I have not made a pie with a top crust using this recipe. I made a pumpkin and pecan pie using this recipe.