Preheat the oven to 350°F. Prepare an 8x8 inch baking dish by lining it with parchment paper, allowing the paper to overhang the dish by a couple inches on each side so that the bars can be lifted out after baking.

In a large bowl, whisk together the melted butter and the sugars until smooth. Add the egg and vanilla whisk together. Add the flour, salt and cinnamon and stir until just combined. Fold in the chopped apples.

Pour the half of the batter into the prepared pan and spread it as evenly as possible - it will be thick. Drizzle the caramel sauce over top of the batter. Cover the caramel sauce with spoonfuls of the remaining batter, spreading it out as evenly as you can.

Bake for 40-45 minutes, or until the blondies are golden brown, and a toothpick inserted in the center comes out with only damp crumbs on it, but no wet batter. Set the pan on a wire rack to cool completely.

Once cool, the bars can be lifted out of the pan using the parchment paper and cut into 16 squares. Store in an airtight container at room temperature.