Combine flour and sugar in a food processor and process to combine. Add butter and pulse until the butter is incorporated and pieces are no larger than the size of a pea. With the machine running, add ¼ cup cold water. The mixture should come together into a crumbly dough that holds together when pinched. If it feels dry and floury, add a very small amount of cold water and process until it reaches the right texture. Turn the dough out onto a flat surface and use your hands to gather it into a cohesive ball. Press into a 6-inch round disk. Wrap in plastic wrap and refrigerate for 30-60 minutes.

After the dough has chilled, unwrap it and place it on a piece of parchment paper dusted with gluten-free flour. Top with another piece of parchment paper. Roll out to about 10-12 inches in diameter. If the edges crack, press them together as best as you can. Remove the top sheet of parchment paper. Quickly and carefully invert the dough onto a 9-inch pie dish. Peel off the bottom sheet of parchment paper. Fit the dough into the pie dish, pinching any cracks back together, as needed. Crimp the edges, as desired, and place in the freezer. Preheat the oven to 425ºF.

In a large bowl, combine all the filling ingredients. Mix well and set aside.

In a medium bowl, combine all the topping ingredients, working them into a crumbly mixture with your fingers.

Remove the crust from the freezer and pour in the apple filling mixture, including the juices. Crumble the topping over the apples and press gently to adhere. Place the pie dish on a rimmed baking sheet.

Place in the oven and immediately reduce the oven temperature to 375ºF. Bake for 50-55 minutes, until golden brown. Let cool completely, then refrigerate for 4-6 hours before slicing and serving. Store leftovers, covered, in the refrigerator for up to 3 days.