Set the oven to 350°F.

Grease a 9x13-inch baking pan with oil or butter.

Line the pan with parchment paper, then grease the paper too.

Peel and chop the apples.

Toss them in a bowl with cinnamon and nutmeg. Set aside.

In a large bowl, mix the melted butter, brown sugar, and granulated sugar using an electric mixer for 1 minute.

Add the eggs and beat for 4 minutes until the mixture is light and fluffy.

Mix in the vanilla extract.

Add the flour, baking powder, salt, cinnamon, and nutmeg. Mix on low until just combined.

Fold in the apples and white chocolate chips with a spatula. The batter will be thick.

Spread the batter evenly in the prepared pan.

Smooth the top with a spatula.

Bake for 35 to 45 minutes, until golden on top and set around the edges. A toothpick inserted should come out clean or with just a few crumbs.

Let the blondies cool for 30 minutes before slicing.

Sift powdered sugar into a bowl.

Add apple cider and whisk until smooth. Add more cider if needed to reach the desired consistency.

Drizzle the glaze over the blondies and sprinkle with cinnamon.

Keep the bars in an airtight container at room temperature for up to 2 days or in the fridge for up to 4 days.

For longer storage, wrap each bar in plastic wrap and place in a container in the freezer for up to 2 months. Thaw overnight in the fridge before serving.

If serving from the fridge, let the bars sit at room temperature for about 30 minutes to soften.