Prep the pan and oven: Preheat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, leaving overhang for easy lifting. Lightly grease the parchment.

Melt the butter: Melt 1/2 cup (1 stick) unsalted butter and let it cool for 3–4 minutes so it’s warm, not hot.

Whisk the wet ingredients: In a large bowl, whisk the melted butter with 3/4 cup light brown sugar and 1/4 cup granulated sugar until glossy. Whisk in 2 large eggs and 2 teaspoons vanilla until smooth.

Mix the dry ingredients: In a separate bowl, combine 1 cup plus 2 tablespoons all-purpose flour, 1 teaspoon baking powder, 1/2 teaspoon fine sea salt, 1 teaspoon ground cinnamon, and a pinch of nutmeg.

Combine: Stir the dry ingredients into the wet just until no flour streaks remain. The batter will be thick.

Add apples and nuts: Fold in 1 1/2 cups finely diced apples (about 2 medium) and 1/2 cup chopped pecans or walnuts if using. Spread the batter evenly into the prepared pan.

Bake: Bake for 25–32 minutes, or until the edges are set and lightly golden and a toothpick comes out with a few moist crumbs. Don’t overbake; blondies should stay fudgy.

Cool: Place the pan on a rack and let the blondies cool at least 20–30 minutes before glazing.

Make the maple glaze: In a small saucepan over low heat, melt 2 tablespoons unsalted butter. Whisk in 1/3 cup pure maple syrup and a pinch of salt. Off the heat, whisk in 1 to 1 1/4 cups powdered sugar until smooth and pourable. If too thick, add 1–2 teaspoons cream or milk. If too thin, add a bit more powdered sugar.

Glaze the blondies: Pour the warm glaze over the cooled blondies and spread to the edges. Let it set 10–15 minutes.

Slice and serve: Use the parchment to lift the slab from the pan. Cut into 16 squares. Serve slightly warm or at room temperature.