Preheat oven to 350°F. For the Cake, grease and flour 2 (9-inch) round cake pans. Mix flour, cornstarch, baking powder, salt and spices in medium bowl. Set aside.
Beat butter and brown sugar in large bowl with electric mixer on medium speed until light and fluffy. Beat in eggs, 1 at a time. Mix in vanilla. Gradually beat in flour mixture alternately with milk on low speed until just blended. Do not overbeat. Pour batter into prepared pans.
Bake 30 to 35 minutes or until toothpick inserted in center comes out clean. Cool in pan 10 minutes. Remove from pans; cool completely on wire rack.
For the Frosting, beat butter, maple syrup and vanilla in large bowl until light and fluffy. Gradually add confectioners' sugar, beating well after each addition and scraping sides and bottom of bowl frequently. Trim edges of cake layers. Place 1 cake layer on serving platter. Spread with 1/2 of the Frosting. Top with second cake layer. Spread top with remaining Frosting.