Preheat the oven to 350°F (175°C). In a mixing bowl, combine flour, brown sugar, and salt. Cut in butter until the mixture resembles coarse crumbs. Stir in rolled oats and pecans. Press the mixture into the bottom of a greased 9x13 inch baking dish and bake for 15 minutes.

Make the Apple Cider Mousse

In a saucepan, simmer apple cider over medium heat until reduced to about 1/2 cup. Let cool. In a bowl, beat cream cheese until smooth. Gradually mix in powdered sugar and vanilla extract. Fold in heavy cream until well combined. Gently fold in the cooled apple cider reduction.

Prepare the Pecan Praline

In a saucepan, combine granulated sugar and water over medium heat, stirring until dissolved. Bring to a boil without stirring until it turns a golden caramel color. Remove from heat and quickly stir in chopped pecans. Pour onto a parchment-lined baking sheet and let cool before breaking into pieces.

Assemble the Bars

Spread the apple cider mousse over the baked crust. Crumble the pecan praline on top, followed by a sprinkle of apple pie spice. Bake for an additional 10 minutes or until set.

Make the Spiced Caramel

In a clean saucepan, combine granulated sugar and water. Cook over medium heat until it melts and becomes caramelized. Stir in apple pie spice and remove from heat. Drizzle over the bars once cooled.

Serve

Let the bars cool completely before slicing. Garnish with fresh apple slices and serve.