Preheat oven to 350 F. Grease a 9-inch round cake pan and line bottom with parchment paper. In a large bowl, beat all ingredients until well blended. Pour into prepared pan and bake 30 minutes or until cake tests done. Cool. Invert onto serving plate and top with Fudge Topping.

In a 2-quart saucepan over medium-high heat, combine cream, sugar, butter, and chocolate and bring to a boil, stirring constantly. Reduce heat to medium and cook 5 minutes more, stirring constantly. Remove from heat and stir in vanilla. Put water and ice in a large mixing bowl. Place pan in bowl and stir until mixture is of spreadable consistency. Stir in nuts. Pour topping evenly over cake, allowing some to run down the sides. The trick is to make sure it is not too runny; let cool to desired consistency before spreading on cake.