1.Preheat oven to 300 degrees. Line an 8 in square baking dish with parchment paper. Set aside.
2.Crust directions: In a medium bowl stir the melted butter, sugar, vanilla, and salt together. Slowly add the flour to the mixture stirring to blend all the ingredients together.
3.Using your hands press the mixture into the baking pan. Bake for 13 to 15 minutes. Should be lightly brown. Let cool on wire rack.
4.Apple Filling directions: In a large mixing bowl add the sliced apples, flour, sugar, water or apple juice, cinnamon, and nutmeg. Continue working with the apples until they are well coated. Set aside
5.. Crumb directions: In a large mixing bowl, combine the oats, brown sugar, cinnamon, and flour. Whisk all ingredients together until they are mixed well. Slowly begin to work the butter into the dry ingredients. Using your hands, work with the mixture until it looks like crumbs. Set aside.
6.Now, increase the temperature of the oven to 350 degrees. Lay the apple mixture on the baked crust. Put the apple slices close together pressing them down into the crust. Sprinkle the crumb topping over the apples. Gently press into the apples. Return to the oven and bake at 350 degrees for 30-35 minutes. Crumb topping should be a golden brown. Set aside to cool on a wire rack for 20 minutes at room temperature. Transfer to the refrigerator for 2 hours to chill. Remove the bars from the baking pan and cut into bars. Enjoy!