Preheat oven to 350 degrees F and prepare a baking sheet with parchment paper
In a medium bowl, combine the all purpose flour, baking soda, cornstarch and salt; set aside
In a mixing bowl with paddle attachment, cream together the unsalted butter, light brown sugar and granulated sugar until combined and creamy
Add the eggs and vanilla extract; Mix until the eggs are fully combined
Slowly add the dry ingredients into the butter mixture and mix until all ingredients are incorporate but do not overmix (scrape down the sides of the bowl to ensure all ingredients are fulling incorporated)
Mix in 1 ½ Cup Semi Sweet Chocolate Chips to the cookie batter (save the remaining ½ cup for the top of the cookies)
Scoop the cookie batter into balls (2 inches round or 2 ½ ounces in weight) and place them 3-4 inches apart on the prepared baking sheet
Top each cookie dough ball with extra chocolate chips and gently press the cookie to flatten the rounded cookie top (do not press the dough to be flat)
Bake the cookies for 11-12 minutes (the edges will be a light golden color and the center will still look slightly undercooked)
Remove the cookies from the oven, sprinkle each cookie with course sea salt and allow them to cool for 5-10 minutes
Enjoy warm or store in an airtight container