Cake: Preheat oven to 180 degrees C. Grease and flour three 20cm cake tins.
Sift together the flour, cocoa, bicarb soda and salt. Set aside.
In a large bowl, cream together the margarine and glucose syrup until light and fluffy. Beat in the eggs one at a time then stir in the vanilla. Beat in the flour mixture alternately with the milk, mixing just until incorporated. Pour batter into prepared cake tins.
Bake in the preheated oven for 25 to 30 minutes or until a toothpick inserted into the centre of the cake comes out clean. Let cool in pans for 10 minutes, then turn out onto a wire rack and cool completely.
Easy Chocolate Icing: In a saucepan, combine butter,cocoa and milk. Cook over low heat stirring constantly until mixture boils. Remove from heat. Gradually beat in icing sugar and continue beating until spreading consistency is achieved. Stir in the vanilla.
To Assemble: Ice between layers, on top and sides with chocolate icing.