Preheat oven to 325°F and line baking sheets with parchment paper.
In a medium bowl, whisk together flour, cornstarch, baking soda, and salt until well combined.
Beat butter, brown sugar, and granulated sugar in a large bowl until light and fluffy, about 4 minutes.
Add eggs one at a time, beating well after each addition, then mix in vanilla extract.
Add the flour mixture to the wet ingredients and mix on low speed just until combined.
Fold in chocolate chips with a spatula, then chill dough for 30 minutes.
Scoop dough into 3-tablespoon portions and roll into tall balls, placing 3 inches apart on baking sheets.
Bake for 12-13 minutes until edges are barely golden but centers look puffy and underdone, then cool on the pan for 10 minutes before transferring to a wire rack.