Preheat the oven to 350 degrees Fahrenheit and line a 13x9 with parchment paper. Spray with non-stick spray and set aside.
Make the crumb first: In a medium bowl, combine butter, brown sugar, flour, salt, and cinnamon. Mix until all ingredients are combined- the mixture should resemble coarse sand. Set aside.
Make the cake: In a large bowl, cream the butter and sugar together. Add eggs, one at a time until all are incorporated. Stir in vanilla.
In a small bowl, combine flour, baking powder, salt, and apple pie spice. Add the dry mixture to the wet mixture in halves, alternating with the buttermilk until all ingredients are mixed. Fold in shredded apples and pour into the prepared pan. Top evenly with crumb mixture.
Bake for 55-60 minutes or until a toothpick inserted in the center comes out clean.
Once fully cool, mix powdered sugar and apple cider together until smooth. Drizzle over the cake and serve.