Preheat oven to 350 degrees. Line three, 8” baking pans with parchment paper. Grease and flour sides of pans (I use Baking PAM for this).
Use electric mixer fitted with paddle attachment to beat butter and sugar until lightened and fluffy, about 3 minutes. Next, beat in vanilla extract.
Add eggs, one at a time, scraping down sides as needed, until well incorporated.
In a medium sized bowl, stir together flour, cornstarch, baking powder, baking soda, and salt.
Starting and ending with buttermilk, alternate beating flour mixture and buttermilk into butter mixture. Do this in at least 3 additions of each.
Divide batter evenly among the prepared pans. Sprinkle chocolate chips evenly over the tops of the three pans (this helps keep chips from all sinking to the bottom).
Bake until toothpick inserted into center of cake comes out with just a few crumbs, about 24 minutes.
Let cool in pan for at least 5 minutes before transferring to rack to cool completely.