Add flour and baking soda to a mixing bowl and whisk for 15 seconds to incorporate and make them fluffy.
To the bowl of a stand mixer, add softened butter and both sugars. Beat with paddle attachment for about 2 minutes, until mixture is smooth and fluffy.
Add egg and vanilla, beat on LOW speed until combined.
Add flour, half the mixture at a time, beating on LOW speed until JUST combined after each addition. Don't overmix, or your cookies won't be soft and tender.
Add chocolate chips and stir together with a wooden spoon.
Cover bowl and chill for at least 30 minutes.
minutes before you want to bake, preheat oven to 350 degrees F. Line a baking sheet with parchment paper and set aside.
Use a large cookie scoop (or a 1/4 cup filled about 2/3 of the way), scoop round balls of dough onto parchment paper about 2 inches apart. I baked 6 cookies per sheet.
Press a couple chocolate chips into the tops of the balls of dough, and bake about 10-12 minutes, or until edges are lightly golden brown and tops of cookies look a little underdone. (mine took 11 minutes).
Sprinkle top of baked cookies with some sea salt flakes.
Allow cookies to cool on the baking sheet for 5 minutes, then transfer to a cooling rack to finish cooling.