Preheat oven to 375°F (190°C). Line a 9×9 pan with parchment paper or grease lightly.
Make the dough: In a large bowl, stir together melted butter, brown sugar, vanilla extract, flour, baking powder, and salt until crumbly dough forms.
Press the base: Use about ⅔ of the dough and press it firmly into the bottom of the pan.
Add the filling: Spread apple pie filling evenly over the base.
Crumble the topping: Take the remaining ⅓ dough and crumble it across the apples.
Bake: Place in the oven for 35–45 minutes, until golden brown on top and the filling is bubbling at the edges.
Cool: Let cool in the pan for at least 1 hour.
Finish: Drizzle salted caramel sauce generously over the cooled bars.
Serve: Slice into 16 squares and serve with ice cream if desired.
