When ready to cook, start your Traeger grill on Smoke with lid open until fire is established (4-5 minutes. Increase temperature to High and preheat with lid closed for 10 to 15 minutes.
Place a cast iron skillet on Traeger and allow to preheat for 10 minutes. Add oil to the pan. Add the onion, apples, pork, brown sugar, salt, and spices.
Cook using a wooden spoon to break up the meat, until it is lightly browned, about 10 minutes. Let the meat mixture cool for 10 minutes, then transfer to a food processor. Add the breadcrumbs and pulse four times to break up any large chunks and set aside.
Crust: In a food processor, combine flour, sage, cheddar and salt. Add the butter and pulse a few seconds at a time until the butter is the size of peas. Add water and vinegar and pulse again until the dough begins to form. Add water, if needed.
Remove the dough from the food processor and form into two discs with your hands. Refrigerate for 30 minutes.
On a floured work surface, roll out the two discs of dough and line a 9-inch pie plate with one of the discs.
Spoon pork filling into the crust. Brush around the edges of dough with egg wash and cover with the second sheet of dough.
Remove any remaining crust and crimp the edges with a fork.
Using a sharp knife, cut several slits in top of crust and brush entire top with egg wash.
Turn Traeger down to 375 degrees F and place pie directly on grill.
Bake for 30 to 40 minutes or until the crust is golden brown. Let rest for 15 minutes and serve. Enjoy!