Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 15x10 inch jellyroll pan.
In a medium bowl, cream together the margarine, butter, and sugar, until smooth. Stir in the egg yolk and vanilla. Combine the flour, salt, and 1/2 teaspoon of cinnamon, stir into the creamed mixture.
Press the mixture evenly into the prepared jellyroll pan. Beat the egg white until frothy, and spread it over the top of the dough. Combine the remaining cinnamon and sugar, sprinkle it and the nuts over the top of the cookies.
Bake for 15 to 17 minutes in the preheated oven. Cut into diamonds while still warm, then cool completely before removing from the pan.