Whisk together the flour, baking soda, salt, and cornstarch.
Use a stand mixer or hand-held mixer to combine the softened butter and sugar in a separate bowl until fluffy.
Add the eggs one at a time, then add the vanilla extract in until just combined.
Mix the dry ingredients in until combined.
Fold in 1 cup of the chocolate chips into the cookie batter.
Line baking sheets with parchment paper.
Use either a mini cookie scoop, or 2 tablespoons of batter to form the cookie balls. Roll with your hands to form a circular shape. Top the balls of cookie dough with the remaining chocolate chips.
Bake the chocolate chip cookies at 350 degrees for 8-11 minutes, until the edges set but not golden brown. You do not want to over bake them.
Remove the cookies from the oven and leave them on the baking sheet for 5 mins, then transfer to a wire cooling rack to cool completely.
Notes
Do not over bake these! This is key for the soft center. The cookies should be set on the edges, but may still be slightly gooey on top when you remove them from the oven. They will continue to cook on the baking sheet while they cool.