1. Preheat your oven to 350°F and line a 9×13 inch baking pan with parchment paper.

2. In a large bowl, mix together the flour, granulated sugar, and salt. Cut in the cold, cubed butter until the mixture resembles coarse crumbs. Press two-thirds of this mixture into the bottom of the prepared baking pan.

3. Bake the crust for 15 minutes until it’s lightly golden. Let it cool slightly while you prepare the apple filling.

4. In a separate bowl, toss the sliced apples with the brown sugar, cinnamon, nutmeg, cornstarch, lemon juice, and vanilla extract.

5. Spread the apple mixture in an even layer over the pre-baked crust. Sprinkle the remaining crumble mixture over the top of the apples.

6. Return the pan to the oven and bake for 35-40 minutes, until the top is golden brown and the apples are tender.

7. Allow the Apple Pie Bars to cool completely in the pan. Using the parchment paper overhang, lift the bars out of the pan and slice them into perfect squares. Drizzle with caramel sauce, if desired.