Instructions

1. Place a rack in the center of the oven and preheat the oven to 350 degrees Fahrenheit. Lightly mist a 12-cup Bundt pan with vegetable oil spray, then dust with flour. Shake our the excess flour. Set the pan aside.
2. Break up the milk chocolate bars into 1-inch piece and place them in a food processor fitted with the steel blade. Pulse on and off 12 to 15 times until the candy is grated but not a powder. (Some pieces may be large and some may be small.) Set the bowl aside.
3. Place the cake mix, pudding mix,sour cream, oil, eggs, and vanills in a large mixing bowl. Blend with an electric mixer on low speed for 1 minute. Stop the machine and scrape down the sides of the bowl with a rubber spatula. Increase the mixer speed to medium and beat 2 minutes more, scrapign the sides down again if needed. The batter should look thick and smooth. Fold in the grated chocolate until it is well distributed. Pour the batter into the prepared pan, smoothing it out with the rubber spatula. Place the pan in the oven.
4. Bake the cake until it is golden brown and springs back when lightly pressed with your finger, 55 to 60 minutes. Remove the pan from the oven and place it on a wire rack to cool for 20 minutes. Run a long, sharp knife around the edge of the cake and invert it onto the rack to cool completely, 20 minutes more.
5. Make the ganache: Place chocolate in a medium heat-proof bowl. Heat the cream in a small saucepan over medium heat until it begins to gently simmer. (Do not let it come to a rapid boil—that’s too hot!) Pour over chocolate, then let it sit for 2–3 minutes to gently soften the chocolate. Stir it together until it is completely combined, then let cool to thicken.
6. Place the cake on your serving dish, and pour chocolate ganache over the top to let it drip down.