Preheat the oven to 350°F (175°C). Line your baking pan with parchment paper or lightly grease it.

In a mixing bowl, combine the dry ingredients: flour, baking soda, baking powder, salt, and nutmeg. Whisk them together and set aside.

In a separate bowl, cream the butter and sugar using a mixer until the mixture is light and fluffy.

Add the egg, vanilla extract, and buttermilk to the creamed mixture. Mix well until everything is fully incorporated.

Gradually add the dry ingredients to the wet mixture. Stir until just combined. Avoid overmixing to maintain a tender texture.

Pour the batter into your prepared pan, spreading it evenly with a spatula.

Bake for 18–20 minutes or until a toothpick inserted in the center comes out clean.

Remove the pan from the oven and let the bars cool in the pan for 10 minutes, then transfer them to a wire rack to cool completely.

While the bars are cooling, prepare the glaze by whisking together the powdered sugar, maple syrup, maple extract, and milk until smooth.

Once the bars are completely cool, spread or drizzle the glaze generously over the top. Allow the glaze to set before serving.