Make the Crust: Preheat your oven to 350°F (175°C) and line a 9×13-inch baking dish with parchment paper. In a medium bowl, combine flour, sugar, and salt. Add the cold cubed butter and mix until the dough is crumbly. Press the mixture evenly into the prepared baking dish. Bake for 15 minutes, or until lightly golden.

Prepare the Apple Filling: In a separate bowl, toss the diced apples with flour, sugar, cinnamon, and nutmeg until evenly coated. Spread the apple mixture evenly over the baked crust.

Add the Crumb Topping: In a bowl, mix together flour, brown sugar, softened butter, and salt until crumbly. Sprinkle the topping evenly over the apple filling.

Bake the Bars: Bake the bars for 35–40 minutes, or until the topping is golden and the apples are tender. Remove from the oven and let cool completely.

Make the Salted Caramel Sauce: In a medium saucepan over medium heat, melt the granulated sugar, stirring constantly until it turns amber. Add the butter and whisk until melted. Slowly pour in the heavy cream while whisking, then add sea salt. Stir to combine and remove from heat. Let the sauce cool slightly.

Serve: Drizzle the cooled salted caramel sauce over the apple pie bars. Slice into bars and enjoy!