In a medium bowl combine dry ingredients, stir to blend evenly. Set aside
In a bowl of an electric mixer fitted with a paddle attachment, cream butter and sugars together, about 5 minutes.
Add egg and vanilla. Mix well.
Reduce speed to low and slowly add dry ingredients until just combined, 15 seconds.
Drop chocolate pieces in and let the mixer just incorporate without breaking chocolate into smaller pieces.
Scoop cookie dough into a ball and wrap with plastic wrap. Place in the refrigerator for 1-2 hours. You can add it to the freezer for 15-20 minutes to speed up the process. You do not want the dough to freeze, just be very chilled and firm.
When ready to bake, preheat the oven to 350°F.
Place one oven rack in the top third of the oven, place another rack in the bottom third of the oven.
Line a baking sheet with parchment paper. Set aside.
Scoop dough into 2” size balls and place on a baking sheet. Leave a generous space between each cookie, minimum of 2”. These cookies will spread out when cooking.
Sprinkle each cookie lightly with sea salt.
Bake on lower oven rack for 9 minutes, then transfer baking sheet to top rack and bake for an additional 9 minutes or until cookies are golden brown.
Transfer to a wire rack to cool and repeat with remaining dough.