Preheat your oven to 350°F (175°C). Line or grease a 9x9 inch baking pan.

In a large mixing bowl, whisk together dry ingredients: flour, baking soda, baking powder, salt, and nutmeg.

In a separate bowl, beat softened butter and sugar until light and fluffy, about 3-4 minutes.

Add egg, vanilla extract, and buttermilk to the butter-sugar mixture and mix until smooth.

Gradually incorporate the dry mixture into the wet ingredients, mixing gently until just combined.

Pour the batter into the prepared pan and bake for 18-20 minutes, or until a toothpick comes out clean.

Allow the bars to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Prepare the glaze by whisking together powdered sugar, maple syrup, maple extract, and milk until smooth.

Spread or drizzle the glaze over the cooled bars and let it set before serving.