Preheat your oven to 350°F (175°C). Grease a bundt pan very well with baking spray that contains flour.
In a large bowl, add the cake mix, pudding mix, sour cream, eggs, oil, water or milk, and vanilla extract.
Mix on low speed until combined. Then mix on medium speed for about 2 minutes until the batter is smooth and thick.
Fold in the mini chocolate chips if using them.
Pour the batter evenly into the prepared bundt pan. Gently tap the pan on the counter to remove large air bubbles.
Bake for 45 to 55 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs.
Let the cake cool in the pan for 10 to 15 minutes. Then carefully invert it onto a cooling rack and let it cool completely.
In a mixing bowl, beat the softened cream cheese and butter until smooth and creamy.
Add the vanilla extract and salt.
Gradually mix in the powdered sugar until the frosting becomes thick and fluffy.
If needed, add 1 to 2 tablespoons of milk or cream to adjust the texture.
Transfer the frosting to a piping bag or zip-top bag with the corner cut off.
Pipe thick lines of frosting from the top edge of the cooled bundt cake down the sides.
Slice and serve.