Aunt Berdena's Chocolate Sheet Cake

Sift into large bowl: 
2 c. flour 
2 c. sugar 
1 t. soda 
2 t. cinnamon (optional) 

Melt in sauce pan: 
¼ lb. margarine (or substitute butter) 
4 T. cocoa 
½ c. shortening 
1 c. water 

Bring mixture in sauce pan to a rapid boil. Pour over dry ingredients and mix. Then add: 
1/2 c. buttermilk 
1 t. vanilla 
3 beaten eggs 

Mix well Pour into cookie sheet. Bake at 400 degree for 20 minutes. Make icing while baking cake. 

Icing: 
½ lb. oleo (or substitute butter) 
4 T. cocoa 
6 T. milk 

Bring to boil and add 1 box powdered sugar and 1 cup chopped nuts. Beat. Spread on warm cake.