Preheat oven to 350 F.

Using an electric mixer with the paddle attachment, cream together butter and sugars on medium speed until light and fluffy, about 2 minutes. Add egg and vanilla and beat in until combined, scraping down the bowl partway through.

In a separate bowl, whisk together flour, cornstarch, baking soda and salt until evenly mixed. Add mixture into the dough, and beat on low speed until combined. Fold in chocolate chips and caramel bits, and stir until just combined.

Measure dough into rounded tablespoon-fulls, and roll into round balls. Place on a parchment-covered baking sheet, and dot with extra chocolate chips if desired. Repeat with remaining dough. Then transfer the cookie sheet to the freezer and chill for 10 minutes.

Transfer sheet to oven and bake for 8-10 minutes, until the tops of the cookies ever so slightly begin to brown. Remove pan and let rest for 5 minutes. Then transfer cookies to a wire rack to finish cooling. Repeat with remaining dough.

Once the cookies have reached room temperature, drizzle with caramel sauce if desired. You can do this by dipping a fork in the caramel sauce and swishing it back and forth over the cookies. Or you can transfer the caramel sauce to a piping bag or ziplock bag and drizzle that way.

Store cookies in an airtight container for up to 5 days.