Step 1

Whisk the flour, baking soda, cornstarch, and salt together in a large bowl. Set aside.

Step 2

In a medium bowl, whisk the melted butter, brown sugar, and granulated sugar together until no brown sugar lumps remain. Whisk in the egg, then the egg yolk. Finally, whisk in the vanilla extract. Pour the wet ingredients into the dry ingredients and mix together with a large spoon or rubber spatula. The dough will be very soft, yet thick. Fold in the chocolate chips. They may not stick to the dough because of the melted butter, but do your best to combine them. Cover the dough and chill in the refrigerator for 3 hours or up to 3-4 days. Chilling is mandatory. I highly recommend chilling the cookie dough overnight for less spreading.

Step 3

Take the dough out of the refrigerator and allow to slightly soften at room temperature for 10 minutes.

Step 4

Preheat oven to 325°F (163°C). Line two large baking sheets with parchment paper or silicone baking mats. (Always recommended for cookies.) Set aside.

Step 5

Roll the dough into balls, 1.5 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. See photo above for a visual. Gently press down on the large cookie dough ball to *slightly* flatten 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 #Bake the cookies for 12-13 minutes. The cookies will look very soft and underbaked. They will continue to bake on the cookie sheet.

Step 6

Allow to cool on the cookie sheet for 10 minutes before transferring 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.