Heat oven to 350 degrees F. Grease and flour three 8 x 2-inch round layer-cake pans.
Sift flour, baking powder, baking soda and cinnamon into bowl.
Beat butter in second bowl until smooth and creamy. Beat in granulated sugar and maple syrup. Add eggs, one at a time, beating after each. Drain potatoes; puree in food processor or mash with fork. Add potatoes and 1/2 teaspoon maple extract to butter mixture; beat until smooth. On low speed, beat in flour mixture just until incorporated. Fold in walnuts. Transfer batter to pans, dividing evenly.
Bake in 350 degree F oven 25 to 30 minutes or until golden brown. Cool in pans on rack 10 minutes. Remove cakes to rack to cool completely.
Beat cream cheese, cream, extract and butter in bowl until smooth. Add confectioners' sugar; beat until good spreading consistency. If necessary, refrigerate to thicken if butter becomes too soft.
Sandwich cake layers together with 3/4 cup frosting between each layer. Frost top and side of cake. Garnish with glace cherries.