Preheat oven to 350ºF. Spray 9.7" fluted tube pan well with vegetable pan spray.
In medium bowl, stir together flour, baking powder and salt. In large bowl, whisk melted butter, sugar, maple syrup, eggs, maple flavoring and milk until smooth. Add flour mixture; whisk in gently until almost incorporated. Gently stir in walnuts. Do not overmix. Pour batter into prepared pan.
Bake 50-60 minutes, or until a cake tester inserted in center come out clean. Cool 20 minutes in pan on a cooling grid. Remove from pan; cool completely before glazing.
In small bowl, mix confectioners' sugar and maple syrup until completely combined. Drizzle over the cooled cake.