• Preheat the oven to 350 degrees. Grease and flour an 8 x 8 inch baking sheet, or, if you want to be able to remove the entire pan of blondies in one piece, line it with foil then grease and flour the foil.
• In a medium bowl, whisk together the butter and brown sugar until smooth. Add the egg and vanilla and whisk until smooth. Add the baking powder, soda, salt, and flour and stir until combined.
• Pour all but about 1/4 cup of batter into the prepared pan. Lay apple slices on top then dot with remaining batter and scatter with pecans if desired. Bake for 25-30 minutes or until blondies are golden and set throughout.

For the glaze:

• Place apple cider in a saucepan over high heat. Bring to a boil then reduce heat to medium high (or whatever temp will maintain a gentle boil), and continue to boil for 15-20 minutes, or until cider is reduced to about 1/2 cup. Add cinnamon, vanilla, and butter, then whisk in powdered sugar until smooth. If you'd like it a little thicker, whisk in a tad more powdered sugar, but remember the mixture will thicken as it cools. Drizzle over the bars and serve within a few hours.