Place a rack in the center of the oven and preheat the oven to 350˚F. Lightly mist a 12-cup Bundt pan with vegetable oil spray, then dust with flour. Shake out the excess flour. Set the pan aside.

Place the cake mix, water, oil, eggs, and vanilla 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, scraping the sides down again if needed. The batter should look thick and well combined.

Measure out 2 cups of the batter and place it in a medium-size bowl. Stir in the corn syrup and pecans. Set the bowl aside.

Break the chocolate bar into pieces, and place those pieces in a small microwave-safe bowl along with the chocolate syrup. Microwave the chocolate at high power for 1 minute and then stir until smooth; return the bowl to the microwave for a few seconds if needed. Fold the melted chocolate into the remaining plain batter until well incorporated.

Pour the chocolate batter into the prepared pan, smoothing it out with the rubber spatula. Spoon the pecan batter evenly over the top. Place the pan in the oven.

Bake the cake until it springs back when lightly pressed with your finger and is just starting to pull away from the sides of the pan, 43 to 47 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 a rack to cool completely, 20 minutes more.

To prepare the glaze, break the chocolate bar into pieces, and place those pieces and the shortening in a small microwave-safe bowl. Microwave at high power for 1 minute, and then stir until the chocolate has melted; return the bowl to the microwave for a few more seconds if needed. Stir in the vanilla. Spoon the glaze over the cooled cake, allowing it to drip down the sides of the cake. Let the cake rest for 10 minutes before slicing.

Slide the cake onto a serving platter. Slice and serve.

Store this cake, in a cake saver or under a glass dome, at room temperature for up to 1 week. (Like it would last for 1 week…I don’t think so!) Or freeze it, wrapped in foil, for up to 6 months. Thaw the cake overnight in the refrigerator before serving.

Notes: I do not add the vanilla to the frosting…for some reason it makes it really thick.

Recipe from: Chocolate Cake Mix Doctor