Prepare the Cake Batter: In a large bowl, mix together the cake mix, sour cream, vegetable oil, eggs, and vanilla extract. Mix until well combined and smooth.
1 box (15.25 oz) yellow cake mix, 1 cup sour cream, ½ cup vegetable oil, 4 large eggs, 1 teaspoon vanilla extract
Bake the Bundt Cake: Pour the batter into a greased and floured Bundt pan. Bake at 350°F (175°C) for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
Cool the Cake: Let the cake cool in the pan for 10 minutes, then invert it onto a wire rack to cool completely.
Make the Custard: While the cake cools, whisk together the instant vanilla pudding mix and milk in a bowl until smooth and thickened.
1 package (3.4 oz) instant vanilla pudding mix, 2 cups milk
Fill the Cake: Once the cake is completely cool, use a long serrated knife to cut a circle in the top of the cake, creating a well. Remove the cut-out cake piece carefully.
Add the Custard: Pour the custard filling into the well. Replace the cut-out cake piece.
Prepare the Ganache: In a microwave-safe bowl, heat the heavy cream for about 45 seconds, or until hot but not boiling. Pour the hot cream over the chocolate chips. Let it sit for a minute, then stir until smooth and glossy.
1 cup semi-sweet chocolate chips, ½ cup heavy cream
Drizzle the Ganache: Pour or drizzle the chocolate ganache over the top of the cake, allowing it to drip down the sides.
Serve: Let the ganache set slightly before slicing and serving. Enjoy!
