Toss together the flour, baking soda, cornstarch and salt in a large bowl. Set aside.
In a medium size bowl, whisk the melted butter, brown sugar, and white sugar together until no brown sugar lumps remain. Whisk in the egg, then the egg yolk. Finally, whisk in the vanilla.
Pour the wet ingredients into the dry ingredients and mix together with a large spoon or rubber spatula. The dough will be very soft. Fold in 1/2 cup chocolate chips. They may not stick to the dough because of the melted butter, but do your best to have them evenly dispersed among the dough. Cover the dough and chill for 2 hours, or up to 3 days. Chilling is mandatory, the longer the better.
Take the dough out of the refrigerator and allow to slightly soften at room temperature for 10 minutes.
Preheat the oven to 325°F degrees. Line two large baking sheets with parchment paper or silicone baking mats. Set aside. Unwrap the Rolos and put remaining 1/2 cup of chocolate chips in a pile.
Roll the dough into balls, about 1 1/2 tablespoons each. You'll have about 30 balls, give or take. The dough will be crumbly, but the warmth of your hands will allow the balls to stay intact. Make a thumbprint into one dough ball and press the Rolo inside. Cover the Rolo with another dough ball and mold the two dough balls around the Rolo, making sure it is completely wrapped inside. Gently press down on the large cookie dough ball to flatten slightly and press a few more chocolate chips on top. Sprinkle with sea salt.
Put 7-8 balls of dough onto each cookie sheet. Put one cookie sheet into the refrigerator as you bake batch #1. Bake the cookies for 12-13 minutes. The cookies will look very soft and underbaked. Do not bake longer than 13 minutes. They will continue to bake on the cookie sheet.
Cool on the cookie sheet for 10 minutes before moving to a wire rack to cool completely. If the cookies still look too puffy when you remove them from the oven, gently press down on them a little more. Cookies stay soft and fresh for 7 whole days at room temperature. Cookies may be frozen up to 3 months. Rolled cookie dough may be frozen up to 3 months and baked in their frozen state for 13-14 minutes.