Generously grease the pie plate with butter and set aside.
Liberally flour a piece of baking paper with tapioca flour on a dry work surface. Place the pastry dough in the centre of the paper and flour it on the top too. I can’t stress this enough – use plenty of tapioca flour. It’s the only way you’ll come out with your sanity intact.
Gently roll the dough out, stopping every couple of rolls to flour both sides of the dough. ‘Turn’ the dough regularly (pick it up and flip it over) to prevent it from sticking. Once the dough gets too big to turn, take another piece of well floured baking paper and place it atop the dough. Working quickly, lift the dough up and flip it onto the newer piece of baking paper. Then you can continue rolling.
If at any point the dough becomes soft and hard to work with, place it flat in the fridge or freezer for a few minutes.
Once you have rolled it out to a couple of sizes larger than the pie plate, place it flat in the freezer for about 5 minutes to get ready for the pie plate.
Gluten free pastry is pretty sensitive, so be ready to patch up tears with your hands.
Lay the pastry flat on a working surface like a table so you have a bit of space underneath for your hands. Place the pie plate gently in the centre of the pastry dough in whatever position maximises pastry overhang.
Use one hand to pull a corner of the baking paper towards you, and place the other directly underneath the centre of the pie dish. As you pull the pastry off the table, your other hand will push the pastry into the pie dish, after which you will quickly flip the dish, letting the pastry fall into it.
Don’t stretch the pastry into the dish – be generous with letting it fall into the dish. Patch up any tears as necessary, and then trim excessive overhang, redistributing it to places that may have none.
Once the whole pie has equal overhang, fold it into the back of the pie dish to create a little wall of pastry. Do this the whole way around.
To crimp the pastry, use a knuckle of one hand to push the dough one way, and your thumb and pointer of the other hand to push into your knuckle, creating a crimp. Repeat the entire way around.
Place the pie on a baking tray so that you don’t crush the crimps with fat oven mitt hands.