Preheat the oven to 350°F. Spray cups of mini-bundt pan well with non-stick spray. Set aside.(See Tip 6)
Whisk together cake mix and chocolate pudding in a large bowl. Add sour cream, mayonnaise, eggs, milk and vegetable oil. Beat on low with electric mixer just until combined.
Add the chocolate chips and fold them into the batter using a silicone spatula.
Using an ice cream scoop, fill cups of pan 2/3 full with batter. Tap the pan on the counter so the batter lays in even layers.
Bake in preheated 350°F oven for 18 to 20 minutes or until a toothpick inserted in the center comes out clean.
Remove the pan from the oven and let the bundtinis cool in the pan for 5 minutes. After 5 minutes, remove from pan and cool completely on wire rack.
Meanwhile, beat the cream cheese, heavy cream and salt on high until light and fluffy.
Gradually beat in the powdered sugar 1 cup at a time, mixing until it's smooth and creamy before adding the next addition. Adjust the amount of confectioners' sugar or cream if needed for desired consistency.
When the bundtinis are completely cooled, transfer to brioche paper cups. Spoon the frosting into a piping bag fitted with a #4B open star tip. (See Tip 7)
Swirl the frosting from the outside to the center top of each of the bundtinis.
Yield: 24 Copycat Chocolate Chocolate Chip Bundtinis. (See Tip 8)