Preheat the oven to 350°F (175°C) and prepare a 9x9 inch baking pan.

Whisk together all-purpose flour, baking soda, baking powder, salt, and ground nutmeg in a mixing bowl.

In a large bowl, beat softened butter and granulated sugar until light and fluffy.

Add egg, vanilla extract, and buttermilk to the butter mixture and blend until smooth.

Gradually mix the dry ingredients into the wet ingredients, being careful not to overmix.

Spread the batter evenly in the prepared baking pan.

Bake for 18-20 minutes or until a toothpick comes out clean.

Allow the bars to cool in the pan for 10 minutes before transferring to a wire rack.

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

Once cooled, generously pour the glaze over the bars and let it set before slicing.