Preheat oven to 350 degrees Fahrenheit and line two baking sheets with parchment paper. Set aside.

In a small bowl, combine flour, cornstarch, baking soda, and salt. Stir and set aside.

In a large bowl, combine butter, brown sugar, and granulated sugar. Mix until fully combined.

Add in the egg and vanilla and mix well.

Stir in the flour mixture and mix until no dry pockets remain.

Fold in the chocolate chips.

Measure the dough into 1/2 cup portions using a measuring cup. It should make six large cookies. Roll balls so they are smooth and place three on each sheet.

Bake one tray at a time, for 17-18 minutes. They will still be soft when they come out so let them cool on the sheet tray for 5-10 minutes.