Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 10 inch Bundt pan.
In a large bowl, cream together the butter and white sugar until light and fluffy. Beat in the eggs one at a time. Gradually blend in 2 cups confectioners' sugar. Beat in the flour and 3/4 cup cocoa powder. Stir in the chopped walnuts. Pour batter into prepared pan.
Bake in the preheated oven for 60 to 65 minutes, or until a toothpick inserted into the center of the cake comes out clean. Let cool in pan for 1 hour, then turn out onto a wire rack and cool completely.
For the glaze: In a small bowl, combine 3/4 cup confectioners' sugar and 1/4 cup cocoa. Stir in milk, a tablespoon at a time, until desired drizzling consistency is achieved. Spoon over cake.