Add flour and baking soda to a mixing bowl and whisk for 15 seconds to incorporate and make them fluffy.
In a separate bowl, add softened butter and both sugars. Beat with a paddle attachment (or hand mixer) for about 2 minutes, until smooth and fluffy.
Add egg and vanilla, beat on low speed until combined.
Add flour mixture half at a time, beating on low speed until just combined after each addition. Don't overmix.
Add chocolate chips and stir together with a wooden spoon.
Cover bowl and chill for at least 30 minutes.
About 15 minutes before baking, preheat oven to 350°F. Line a baking sheet with parchment paper.
Using a large cookie scoop, scoop round balls of dough onto parchment paper about 2 inches apart, 6 cookies per sheet. Press a couple chocolate chips into the tops of the dough balls.
Bake 10–12 minutes, until edges are lightly golden brown and tops look slightly underdone.
Sprinkle tops of baked cookies with sea salt flakes. Allow to cool on the baking sheet for 5 minutes, then transfer to a cooling rack.