In a large bowl using a handheld mixer or stand mixer with paddle attachment, beat the butter, brown sugar, and granulated sugar together until fluffy and light in color. Mix in egg and vanilla extract. Scrape down the sides and bottom of the bowl as needed.

In a separate bowl, combine flour, cornstarch, baking soda and salt. On low speed, slowly mix into the wet ingredients until combined. The cookie dough will be thick. Add the chocolate chips and pecans, then mix until evenly distributed. Cover dough tightly with aluminum foil or plastic wrap and chill for at least 1 hour and up to 3-4 days. Chilling is mandatory for this cookie dough so the cookies don’t over-spread.

Remove cookie dough from the refrigerator and allow to sit at room temperature for 10 minutes. Preheat oven to 350°F (177°C). Line 2 large baking sheets with parchment paper or silicone baking mats. (Always recommended for cookies.) Set aside.

The cookie dough will be slightly crumbly, but will come together as you roll into individual balls with your hands. Roll balls of dough, about 1.5 Tablespoons of dough each (a medium cookie scoop is helpful), and arrange 3 inches apart on the prepared baking sheets. Press a few pieces of caramel onto the tops of the cookies and sprinkle each with sea salt.

Bake for 11-12 minutes, until barely golden brown around the edges. The centers will look soft.

Remove from the oven and allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.