Pulse the flour, sugar and salt in your food processor until combined.
Sprinkle over the shards of vegetable shortening and pulse for around 10 seconds until the mixture looks crumbly.
Add the butter cubes and pulse until the mixture resembles chunky sand - sounds delicious, right? ;-).
Add the ice-cold water to the mixture while pulsing your food processor one tablespoon at a time. You are looking for a dry-ish playdough looking mass (shaggy mass) that will hold together when you pinch it between your fingers. Stop adding water once you have that.
Turn the dough out onto a bench and bring it together with your hands to form a disc.
Wrap the disc in cling film and pop it in the refrigerator for at least 30 minutes before use.
When you are ready to use your dough, pull it from the refrigerator and let it sit for 5 to 10 minutes until it is soft enough to roll out and line your pie pan.