3 1/2 sticks (14 ounces) butter, at room temperature, plus more for the pan
1 3/4 cups granulated sugar
6 large eggs
2 cups confectioners' sugar
2 1/4 cups all-purpose flour, plus more for the pan
3/4 cup unsweetened cocoa powder
2 cups (8 ounces) chopped walnuts
3/4 cup confectioners' sugar
1/4 cup unsweetened cocoa powder
1 1/2 to 3 tbsp milk
Adjust the oven rack to the middle position and preheat oven to 350º. Butter a 12 cup bundt pan. Dust with flour and shake out any excess.
In a large bowl using an electric mixer, beat the butter and granulated sugar until light and fluffy, 1 to 2 minutes. Add the eggs, one at a time, beating well after each addition.
Gradually add the confectioners' sugar, beating until combined. Using a spoon, stir in the flour, cocoa and walnuts, and mix until combined. Scrape the batter into the prepared pan and spread it evenly.
Bake for 56 to 58 minutes. (Because this cake has a soft center, an ordinary doneness test cannot be used. Accurate oven temperature and baking time are critical. The surface will have a thin crust but will not appear to be done). Transfer the pan to a wire rack to cool for 1 hour. Invert onto a serving plate and set aside to cool completely.
In a small bowl, combine the confectioners' sugar, cocoa, and 1 1/2 tbsp milk. Mix until well-blended, adding some of the remaining milk, 1/2 tbsp at a time. if necessary to achieve a spreadable consistency.
Spoon the glaze over the top of the cooled cake, allowing some to run down the sides.
12 to 14 servings