Preheat oven to 350 degrees F (180 C) and line an 8x8 inch pan with parchment. Add the water to a medium saucepan over medium high heat and add your apples. Cook for 7 to 8 minutes, stirring often, until the apples are starting to get soft and darken. Combine the salt, sugar, cinnamon, and cornstarch in a small bowl and mix to combine, then add to the pan. Continue cooking for about 2 minutes longer until, stirring constantly, until the sugar starts to melt and caramelize. Remove pan from heat and set aside until needed.
Cookie Bar Dough:
In a medium mixing bowl, beat coconut oil, nut butter, almond milk, and brown sugar together until creamed. Add, baking powder, salt, vanilla, and cinnamon and beat until mixed. Add the flour and graham crumbs and beat until well combined.
Use a rubber spatula to spread about 1/2 of the dough in the baking dish and bake for about 8 - 10 minutes until the top starts just barely browning. Remove from oven and scrape out your pan of apple mixture over the dough. Spread to even out then crumble the remaining 1/2 of the dough over top and return to the oven for 15 to 17 minutes until the top is starting to turn golden brown. Remove pan from oven and let cool for at least 20 minutes before cutting.
Icing:
Whisk the, milk, vanilla, and salt in a small bowl. Add the powdered sugar and stir gently until you have a smooth icing. Use a fork or fine tipped pastry bag to drizzle over the bars after you cut them.
Recipe Notes
*If you are vegan and prefer to not make your own graham crackers you can replace the crumbs in this recipe with a number of lightly sweet cookies or crackers from the store. I think Nabisco makes grahams without honey but Speculoos and Biscoff Speculoos cookies, animal crackers, cinnamon teddy grahams, and Girl Scout's Thanks-a-lots are all vegan. Double check to make sure though.