Preheat your oven to 350°F (175°C) and line an 11x7 inch pan with tin foil or coat it lightly with cooking spray.

In a medium saucepan, combine the finely chopped apples, brown sugar, butter, vanilla extract, and cinnamon. Cook over medium-low heat for 3-4 minutes until the apples soften.

In a large mixing bowl, cream the softened butter until light and fluffy. Gradually add the sugars and mix well. Beat in the eggs, stir in the vanilla extract and salt. In a separate bowl, whisk together the flour, baking powder, and cinnamon before folding into the wet mixture until combined.

Spread half of the blondie batter into the prepared pan. Spoon the warm apple filling over this layer and drop spoonfuls of the remaining batter on top, spread to cover the apples.

Bake the blondies for 25-30 minutes until the top is golden brown and a toothpick comes out clean. Keep an eye on them to prevent overbaking.

To make the maple glaze, melt butter, maple syrup, and vanilla in a small saucepan over low heat. Sift in the powdered sugar, whisking until smooth. Allow to cool for 8-10 minutes.

After cooling the blondies for 10 minutes, lift them out using the foil, drizzle the glaze over the top, let it set, then slice into squares.