Begin making the pie crust by whisk together flour and baking powder in a large mixing bowl.
In seperate smaller mixing bowel whisk together olive oil, apple cider, and water.
Slowly add liquid ingredients to dry ingredients and mixed until a dough forms.
Wrap in waxed paper or kitchen wrap and let dough chill until firm.
Once dough is firm, separate into two discs and roll out between two sheets of waxed paper to make your top and bottom crust. Dough should be about the thickness of two stacked quarters. Place bottom crust in pan and press into place.
Wash, peel, core and slice apples and toss in a large mixing bowl with flour, cinnamon, nutmeg, and cornstarch. When apples are evenly coated add maple syrup and mix all ingredients.
Pile prepared apples into pie pan. Lay top crust over apples and firmly press the crusts together. Slash steam vents in the crust.
Mix an egg in separate bowl and brush the top crust with the egg wash.
Place pie on baking sheet and bake for 20 minutes until crust is golden. Lightly cover with aluminium foil and cook for another hour and 10 minutes.
Let cool for 1-2 hours before cutting.