1Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x13 inch pan.
2In a medium bowl, combine the sugar, brown sugar, flour, and butter; blend with a pastry blender until the mixture is in coarse crumbs. Remove 2 cups of the mixture to another bowl, and reserve the rest.
3Stir the coconut and walnuts into the 2 cups of the sugar mixture. Pat firmly into the greased pan. Stir the baking soda, salt, and cinnamon into the reserved mixture. Then mix in the egg, buttermilk and vanilla until well blended. Spread this over the crust in the pan.
4Bake for 35 to 45 minutes in the preheated oven, or until firm. Allow to cool. Make a glaze using confectioners' sugar and enough of the milk to give it a drizzling consistency. Drizzle over bars before cutting into squares.