Chocolate Sheet Cake

1 1/4 cup butter/margarine
1/2 tsp. salt
1/2 cup unsweetened cocoa
2 eggs
1 can sweetened condensed milk
1 cup water
2 cups flour
1 cup confectioners sugar
1 tsp. baking soda
1 tsp. cinnamon
1 cup chopped nuts 

Preheat oven to 350 F. In small saucepan, melt 1 cup margarine. Stir in cocoa and water. Bring to a boil. Remove from heat. In large bowl, combine flour, brown sugar, baking soda, cinnamon and salt. Add cocoa mixture and beat well. Stir in 1/3 cup milk, eggs and vanilla. Pour into greased 15x10 jelly roll pan. Bake 15 minutes or until cake springs back when lightly touched. In small sauce pan, melt remaining 1/4 cup margarine, add remaining cocoa and milk. Stir in confectioners sugar and nuts. Spread on warm cake.