Tunnel of Fudge Cake

Make the filling: In a medium pan, combine 1 1/2 cups milk and pudding mix. Cook as directed on the package. Add chocolate chips and stir until melted. Set aside.

Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 10-inch Bundt or tube pan.

Make the cake batter: In a large bowl, combine white sugar, butter, and shortening. Beat until light and fluffy. Add vanilla and eggs. Mix well.

Add flour, 1/2 cup cocoa, baking powder, salt, and 1 cup milk to a bowl. Beat on low speed until moistened. Beat on medium speed for 3 minutes, then stir in walnuts.

Reserve 2 cups of the batter. Pour remaining batter into the prepared pan. Spoon the filling in a ring on top of the batter, making sure it does not touch the sides of the pan. Spoon reserved batter over the filling.

Bake in the preheated oven until the cake springs back when touched lightly in the center, 50 to 60 minutes. Cool for 1 hour in the pan, then turn out onto a wire rack and cool completely.

Make the glaze: In a small bowl, combine confectioners' sugar and remaining 1/4 cup cocoa. Stir in enough milk to reach desired drizzling consistency. Spoon glaze over the cooled cake, allowing some to run down the sides.