Preheat your oven to a moderate 350°F (175°C) to get ready for baking.
In a food processor, combine the almond flour, oat fiber, your chosen sweetener, and xanthan gum. Give it a quick pulse until everything is well mixed.
Add the cold, cubed butter and cream cheese to the mixture. Pulse briefly again, just until you see coarse, crumbly bits form. Be careful not to overmix!
Now, add the beaten egg and pulse until the dough just begins to come together in a clump. The key is to avoid overmixing, which can melt the fats and affect the flakiness.
Transfer the dough onto a piece of plastic wrap. Gently form it into a flat disk, cover tightly, and chill in the refrigerator for at least 1 hour, or even overnight. This step makes the dough much easier to handle.
When you're ready to bake, place the chilled dough between two sheets of parchment paper. Use a rolling pin to roll it out into a circle that matches the size of your pie dish. Don't worry if it tears a little; it's easy to press back into shape!
Carefully transfer the rolled dough into your pie dish. You can either leave the edges plain or elegantly crimp them with your fingers. Use a fork to gently prick the bottom of the crust all over; this prevents it from puffing up while baking.
Bake your crust on the center oven rack. If your pie filling doesn't require baking, bake the crust for 15-18 minutes until golden. If your filling will be baked, pre-bake the crust for a shorter 5-10 minutes, depending on the filling's baking time.