In a mixing bowl, beat together the butter, granulated sugar, and brown sugar until creamy and well combined, about 2-3 minutes. Add the egg and vanilla; mix until incorporated.

In a separate bowl, whisk together the flour, cornstarch, baking soda, baking powder, and sea salt. Mix until combined.

Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. Fold in chocolate chips and caramel pieces.

Cover the dough and chill in the refrigerator for at least 1 hour.

Preheat the oven to 350°F (180°C). Line a baking sheet with parchment paper.

Scoop the dough and roll into balls. Place on the baking sheet, spaced 2 inches apart, and gently press in extra chocolate chips on top.

Bake for 12-15 minutes until edges are firm and centers appear soft.

Cool on the baking sheet for about 5 minutes before transferring to a wire rack.