1 1/2 cups peeled and finely diced apples (such as Granny Smith or Honeycrisp)
Instructions
Preheat your oven to 350°F (175°C). Grease an 8×8-inch square baking pan or line it with parchment paper, leaving an overhang on the sides for easy removal later.
In a small saucepan over medium heat, melt the butter. Continue cooking, swirling the pan occasionally. The butter will foam up and then begin to develop little brown flecks at the bottom. Once it smells nutty and turns a golden amber color, remove it from the heat immediately and pour it into a large mixing bowl to cool slightly.
Add the brown sugar and maple syrup to the bowl with the browned butter. Whisk until smooth. Add the egg and vanilla extract, beating vigorously until the mixture is well combined and slightly glossy.
In a separate medium bowl, whisk together the all-purpose flour, cinnamon, nutmeg, baking powder, and salt. Ensure there are no large lumps of spices.
Gently stir the dry ingredients into the wet ingredients using a spatula until just combined. Do not overmix. Fold in the diced apples until they are evenly distributed throughout the thick batter.
Spread the batter into the prepared baking pan, smoothing the top with a spatula. Bake for 25 to 30 minutes, or until the edges are golden and a toothpick inserted into the center comes out with just a few moist crumbs. Let the blondies cool completely in the pan before slicing.