Preheat oven to 300 degrees. Spray 9×9 pan with non-stick spray and set aside.

For the crust mix the butter, sugar, vanilla and salt in bowl until combined. Add flour and mix again. Using your hands press the crust mixture into the 9×9 pan until all mixture is evenly distributed. Bake for 15 minutes.

While the crust is baking prepare the apple filling. Put sliced apples in large bowl. Pour flour, sugar, cinnamon and nutmeg and stir until apples are coated. Set aside.

To make the crumb topping combine the oats, brown sugar, cinnamon, and flour in small bowl. Use your hands or a pastry blender to mix in the butter until the mixture is crumbly. Set aside.

Remove crust from the oven and then preheat oven to 350 degrees. Pour the apple mixture on top of warm crust and use the back of a spoon to press down the apples to lay across smoothly. Sprinkle the crumb topping on top of apples until covered. Bake for 30-35 minutes, or until golden brown.

Remove from oven and let rest for 20 minutes at room temperature. Then place in the fridge to set for at least 2 hours. Cut apple pie bars and serve warm or cold. Drizzle the carmel sauce on top just before serving. Enjoy!