Preheat oven to 400 degrees F, line a baking sheet or stone with parchment and set aside.
In the bowl of a stand or hand mixer fitted with the paddle attachment, combine the flour, salt, and cubed butter. Mix for 1-2 minutes until incorporated. With the mixer on low, slowly pour in the cold water until a dough starts to form. The dough should start to pull away from the sides of the bowl.
Transfer the dough to a lightly floured surface and knead 3-4 times, using a rolling pin, roll the dough out into a large circle about 1/4" thick. Transfer the dough to the prepared baking sheet.*
Combine 2 tablespoons of sugar and the remaining 2 tablespoons of flour and sprinkle evenly over the dough. Spread the applesauce out thinly in the middle of the dough, leaving about an inch uncovered around the outside.
Arrange the sliced apples in an even layer on top of the applesauce.* Fold the dough inwards to create a crust.
Brush everything with the melted butter and sprinkle the remaining sugar on top. Allow to chill for 10-15 minutes before baking. Bake at 400, for 55-60 minutes until the apples are tender and the crust is golden brown. Allow to cool before slicing.
Notes
*To easily transfer the pie dough onto the baking sheet - losely roll it around the rolling pin and unroll on the prepared sheet.*You can layer the apples in an even layer or make a concentric design if desired.