In a medium bowl, combine 3/4 cup sugar, 3 tablespoons cocoa, baking powder and salt. Blend in milk, melted butter, vanilla, and nuts. Beat until smooth. Pour batter into a square 8" x 8" x 2" pan and set aside.
In a small bowl, combine remaining 1/2 cup sugar, brown sugar, and remaining 4 tablespoons cocoa. Mix until blended. Sprinkle mixture evenly over batter. Pour hot water over top. Do NOT stir.
4Bake 40 minutes or until center is almost set.
Let stand 15 minutes, spoon into dessert dishes and garnish with whipped cream or ice cream.