Preheat oven to 350 degrees. In large mixing bowl, beat well egg yolk, sugar and sour cream. Dissolve baking soda and salt in water to make a paste, blend into mixture. Add half of the flour until well combined then add remaining flour-it will be thick. Slowly pour 1/4 cup maple syrup into one stiffly beaten, but not dry, egg white beating on high speed while pouring. Fold in the egg white mixture to the batter and add nuts if desired. Bake in greased 9-inch cake pan until toothpick inserted in center comes out clean-approximately 40 minutes. Top with maple glaze.

Maple Glaze: Boil together and then completely cool.

Maplehurst Chef at the "Maplehurst Inn", Antrim, N.H.