Tunnel of Fudge Cake

Instructions

1. Preheat the oven to 350°F. Grease and flour a 10-inch bundt pan, making sure to get into all of the nooks and crannies of the pan.
2. In the bowl of a stand mixer fitted with the paddle attachment, combine the sugar and butter; beat on medium-high speed until light and fluffy, 3 to 5 minutes.
3. Add the eggs, one at a time, beating well after each addition and pausing to scrape the sides of the bowl with a rubber spatula as needed. Gradually add the powdered sugar; blend well. Remove the bowl from the mixer.
4. Sift the flour with the cocoa powder; add this mixture, about 1 cup at a time, to the batter. Stir it by hand, using a wooden spoon, until the dry ingredients are just combined. Stir in the nuts.
5. Spoon the batter into the prepared pan; spread evenly, leveling the top with a rubber spatula.
6. Bake for 45 to 50 minutes, or until top is set and edges are beginning to pull away from side of pan (a cake tester or toothpick inserted into the center of the cake will still be gooey). Cool upright in the pan on a wire rack until just slightly warm, about 1½ hours. Invert onto a serving plate; cool for at least 2 hours more (this will allow the filling to set).
7. Sift together the powdered sugar and cocoa into a medium bowl. Whisk in just enough milk for your desired drizzling consistency. Spoon the glaze over the top of the cake, allowing some to run down the sides. Store in the refrigerator, tightly covered, for up to 3 days. Let come to room temperature before serving.