Combine flour, sugar and salt in food processor. Pulse a few times to combine
Add in butter cubes and pulse until you have pea size crumbs.
Slowly stream in the ice water and pulse until combined. (Dough will be ready when it holds it shape when you squeeze it in your hands)
Add 1 tbsp more water if necessary if dough is too dry.
Dump out onto a lightly flour surface and form into a disk. Wrap with plastic wrap and refrigerate for at least 1 hour.
Place sliced apples, pumpkin butter, lemon juice, flour, sugar, cinnamon and salt in medium size bowl. Toss to combine.
Lightly whisk egg in small bowl and set aside.
Combine oats, flour, sugar, cinnamon and salt. Stir to combine.
Add in butter and using pastry cutter or with a fork, cut the butter into the mixture until fully incorporated. You should have dime size crumbs.
Preheat oven to 375 and line a baking sheet or cooking stone with parchment paper.
Roll dough out on lightly floured surface to 12-14" circle (It doesn't have to be perfectly round or uniform!)
Place apple filling in middle of the dough, leaving about a 3" border.
Fold in edges over the apples, overlapping every couple of inches.
Top with crumb topping (you may have some leftover).
Lightly brush dough with egg wash.
Bake for 45-60 minutes until crust is golden brown, rotating halfway in between.
Serve warm with whipped cream or vanilla ice cream (optional).
*Click here for my easy homemade Pumpkin Butter recipe!
*To make ahead: make dough and keep in refrigerator for up to 3 days or in freezer for up to 6 months. Crumb topping can also be made and stored in airtight container for 1 week in refrigerator or 6 months in freezer.
*Make sure to use firm apples such as Granny Smith, Gala or Honey crisp so they don't get mushy or mealy once baked.