01 - 
                Preheat oven to 175°C. Grease and flour an 20x20 cm baking pan or line it with parchment paper ensuring corners are fully covered to prevent sticking.
              
              
              
                02 - 
                In a medium bowl, whisk together flour, baking powder, salt, cinnamon, and nutmeg until uniformly combined and free of lumps.
              
              
              
                03 - 
                In a large bowl, whisk melted butter with brown sugar until mostly dissolved and glossy to achieve a tender crumb.
              
              
              
                04 - 
                Add eggs one at a time, whisking thoroughly after each addition, then mix in vanilla extract until batter is smooth and slightly lightened in color.
              
              
              
                05 - 
                Gradually fold dry mixture into wet ingredients carefully, mixing until just combined to avoid developing gluten which would toughen the texture.
              
              
              
                06 - 
                Gently fold chopped apples into the batter with a spatula, ensuring even distribution while maintaining batter lightness.
              
              
              
                07 - 
                Transfer batter to prepared pan, spreading evenly to edges with a spatula. Bake on middle rack for 30 to 35 minutes, checking at 30 minutes with a toothpick; it should come out clean or with moist crumbs.
              
              
              
                08 - 
                Allow brownies to cool fully in the pan to firm up and prevent crumbling when cut.
              
              
              
                09 - 
                Whisk powdered sugar and maple syrup in a small bowl. Gradually add milk until the glaze flows in ribbons but remains thick enough to hold shape.
              
              
              
                10 - 
                Drizzle glaze over cooled brownies using a fork for fine lines or spoon for thicker coverage. Slice into squares and serve.