For cake: Melt 1 cup margarine in a saucepan, stir in 1/4 cup cocoa & 1 cup water. Bring to a boil and remove from heat.
In a bowl, mix 2 cups all purpose flour, 1 1/2 cup brown sugar, 1/2 tsp. salt, 1 tsp. soda, & 1 tsp. cinnamon, add to the warm cocoa mixture and beat well. Sir in 1/3 cup Eagle Brand Milk, 2 eggs & 1 tsp. vanilla.
Bake for 15 minutes at 350 degrees in a greased and floured 14 1/2" x 9 1/2" cake pan.
Prepare icing while cake is baking.
Melt 1/4 cup margarine & 1/4 cup cocoa in a saucepan or in a microwave. Remove from heat. Sir in the rest of the can of Eagle Brand Milk, 1 cup powdered sugar, & 1 cup nuts. Pour over warm cake.