Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking dish with butter or line it with parchment paper.

In a medium bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, and nutmeg.

In a large mixing bowl, combine the softened unsalted butter with the packed light brown sugar and cream the mixture until light and fluffy.

Beat in one large egg and a teaspoon of pure vanilla extract into the creamed mixture until well combined.

Gradually add your prepared dry ingredients to the wet mixture, alternating with ¾ cup of buttermilk, mixing just until combined.

Gently fold in ½ cup of pure maple syrup into the batter until fully incorporated.

Carefully pour the batter into your prepared baking dish, spreading it evenly across the surface.

Place the baking dish in the preheated oven and let it bake for 20-25 minutes, checking for doneness with a toothpick.

While the bars are baking, whisk together 1 cup of powdered sugar and 2 tablespoons of pure maple syrup in a medium bowl for the glaze.

Let the bars cool in the baking dish for about 10 minutes, then transfer them to a wire rack to cool completely.

Once the bars have cooled, drizzle the maple glaze over the top, let it set for a few minutes, and then slice into bars.