Preheat oven to 350 degrees F. Spray a 9-inch bundt pan with nonstick spray and set aside.
In a large bowl, beat sugar and butter until light and fluffy. Add the remaining ingredients, and beat at low speed until mixed, scraping the sides of the bowl as needed. Increase the mixing speed to medium and beat for 4 minutes. Fold in walnuts, if using.
Spoon batter into prepared pan and bake at 350 for 50 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, the remove from the pan and allow to cool completely on a wire rack.
for the frosting:
Heat brown sugar, butter and milk in a 1-quart saucepan until the mixture boils and the sugar dissolves, stirring constantly. Remove from the heat and cool slightly.
In a small bowl at high speed, beat powdered sugar, maple extract and brown sugar mixture until smooth. Spoon over the top of your cooled cake.
Recipe by Kitchen Meets Girl at https://kitchenmeetsgirl.com/brown-sugar-pound-cake/