First make the crust dough.
Add room temperature butter (not cold, you want to be able to smash it with a fork) to a mixing bowl. Add flour & salt & cut the butter into the flour with a pastry cutter, fork or food processor. You want pea sized bits of butter covered with flour. Add maple syrup and egg and stir. Add ice water 1 tablespoon at a time until dough comes together. Form into a disk, wrap and refrigerate.
To make filling:
First, peel and slice 5-6 large apples. I used Gala because that’s all I had in the house. Toss the apple slices, butter, maple syrup, salt and cinnamon into the cast iron skillet. Let cook on medium until the apples are soft.
Stir in the flour. The sauce will thicken. Remove from heat and set aside.
Next, grab your dough from the refrigerator.
Roll out your dough on a lightly floured surface (it helps if you do this on a sheet of parchment or plastic). Flour the surface, place your dough, flour the top of the dough disk & roll out with your rolling pin. Start from the center and roll out toward the edges. To move pie crust, roll crust loosely over a rolling pin & unroll into the cast iron skillet. Trim any excess crust off.
Cut slits in the crust to vent. Brush with butter. Dust with cinnamon or a cinnamon/sugar mixture.
Bake at 350 until it’s done (about 30 mintues).