Prepare crust by adding flour and salt to medium mixing bowl. Stir to incorporate. Grate in butter and stir as you go to keep from clumping. Alternatively, you can also pulse in a food processor.
Slowly add water, first only adding 1/4 c. and then remainder (and more if needed) just until dough clumps together. On lightly floured surface, kneed once or twice until it forms a ball. Place in fridge on a plate for a few minutes to help with the rolling out process.
Preheat oven to 375 degrees and lightly grease a pie pan. On your lightly floured surface, use a rolling pin to roll it out into a wide disk, about 1/4″ thick. Using a floured spatula, start loosening the dough on the edges so it doesn't break. Carefully lift dough over tart pan and press in gently with your fingers on only the base.
Place in fridge to allow to cool for about 5 minutes before crimping the top (this helps again to chill since using gluten free flour). Remove from fridge and crimp the top, or you can leave it open as I did to allow for a more rustic look. Prick base of pan to allow for air flow with fork.
Pre bake crust for approximately 12-15 minutes or until 60% baked through. In the meantime, prepare filling and when crust is done, remove from oven and set aside.