Adjust oven racks to the upper-middle and lower-middle positions. Preheat the oven to 325º. Line two cookie sheets with parchment paper or a silicone baking mat.
Whisk the flour, baking soda, and salt together in a medium bowl; set aside (I do this rarely).
In a stand mixer fitted with the beater attachment, beat the butter and sugars at medium speed until thoroughly combined and airy, about 1-2 minutes. Add the whole egg, egg yolk, and vanilla and beat on medium-low until incorporated, about 30 seconds, scraping down the sides of the bowl and beater as need with a rubber spatula. Add the dry ingredients and mix on low speed just until combined, at most 30 seconds. Pour in the chocolate chips and again mix on low briefly until incorporated.
Scoop up about a half-cup of dough and roll it into a rough ball. Pull the dough apart into two equal halves. Rotate the halves 90 degrees and, with the jagged surfaces facing up, place the cookies on prepared baking sheets, spacing about 2½ inches apart. To fancy these up, sprinkle a pinch of flaky sea salt on top (I use Maldon).
Bake until the cookies are light golden brown and the edges just start to harden but the centers are still soft and puffy, 15 to 17 minutes, switching and rotating the baking sheets halfway through the baking time. Do not overbake.
Cool the cookies on the baking sheets until they are stable enough not to bake. Transfer to a wire cooling rack to cool completely, though eating them while warm is highly recommended.
*These cookies are bakery-style large. If making them for a school class, I use a #40 cookie scoop, which will produce a larger yield and a smaller sugar-high to manage.