Whisk together the flour, sugar, and sea salt.

Cut each tablespoon of cold butter into small, 1/4" squares, then work or "cut" the butter into the flour mixture (all the butter at the same time) until it's crumbly. A few larger, pea-sized chunks of butter will still remain when you are finished. This is a helpful video on how to do this. You can use either your fingers, two knives, or a handheld pastry blender (easiest and fastest method).

Dissolve the gelatin in the hot water in a small bowl. Stir until thoroughly blended.

Whisk the beaten egg and gelatin mixture together until very foamy. Blend into the dry ingredients and mix until a thickened dough forms. I like to use lightly oiled hands to do this.

Shape the dough into a ball and chill in the refrigerator for at least an hour, or up to overnight.

Remove dough from refrigerator and allow to rest at room temperature for 10 to 15 minutes before rolling it out.

Preheat the oven to 375°F/ 190°C

Lightly grease 9" pie pan.

Roll out dough to about 1/8" (4 mm) thickness on a piece of unbleached parchment paper sprinkled with gluten free flour. Carefully invert the crust into the greased pie pan (I actually prefer to press out the crust with my hands directly in the greased glass pie pan).

Pre-bake pie crust for 12-15 minutes or until the crust begins to toast slightly to a golden brown around the edges.

Cool the crust until you can touch it comfortably before pouring in filling of choice and baking the pie as directed.