Before anything else, preheat the oven to 325 degrees Fahrenheit. Then, grease and line the cake pan with parchment paper.
Afterward, prepare the bowl of your hand or stand mixer, attached with a whisk attachment. Then, beat in the cake mix, cake flour, sugar, and kosher salt. Make sure to beat till all the ingredients incorporate well.
Then in another bowl, whisk in the sour cream, eggs, water, and vanilla.
Next, at low speed, gradually add the wet ingredients to the dry mixture at medium speed. Do not forget to scrape the sides and bottom of the bowl using a rubber spatula. Mix in until the cake batter incorporates thoroughly.
Now drop in all the mini chocolate chips and fold them in the batter evenly.
Afterward, pour the batter into the greased pans and bake it into the preheated oven for twenty to thirty minutes. Use a skewer to check and poke the center. Make sure to check if it comes out clean since it is done if it does; however if you see crumbs stuck on the stick, it needs more time.
Finally, allow the cake to cool on a wire rack fully. Decorate with frosting if desired. Keep refrigerated until five days.