Preheat oven to 205°C. Line 2 baking sheets with parchment paper.
Whisk together flour, baking soda, salt. Set aside.
With a stand or hand mixer (or whisking vigorously by hand) beat cold butter until smooth and creamy, 2 minutes. (By hand, smear butter against sides of bowl with a wooden spoon before whisking so it doesn’t lump up in the whisk.)
Add sugars. Cream together until paler and fluffy, 3-4 minutes.
Beat in egg, egg yolk, and vanilla until fully incorporated.
Add pre-whisked dry ingredients all at once and mix until just barely combined in a soft dough.
Fold in chocolate chips. Do not overmix: It can result in flat or tough cookies.
Let the dough rest (at room temp or in fridge) 5 minutes so flour absorbs moisture.
Use an ice cream scoop (or big spoonfuls) to scoop dough balls the size of ping pong balls. Do not roll the balls smooth; leave them craggy. When placing on baking sheet (at least 3” apart), roughly shape them into “towers” taller than they are wide.
Bake 1 tray at a time for 8-11 minutes until the edges are crisping, wrinkled, and golden brown, light honey-color. The centers should be just barely set: uniformly light golden brown, with no patches of pale dough-color or shiny liquid areas. Do not overbake. They will finish cooking as they cool.
Let cool on tray at least 10 minutes to fully set.
NOTES
Chilling: Ideally, you would chill the cookie dough in the fridge for at least 1 hour before scooping and baking.
5 minute rest: Resting dough 5 minutes after mixing dry and wet ingredients = flour absorbs moisture and becomes firmer, again preventing oven spread. (This also happens during chilling.) I do the same thing with the enriched dough I use for monkey bread, cinnamon rolls, etc. (With that dough, the difference is more stark—in 5 minutes, it goes from sticky gloop to smooth, kneadable dough.)
Oven temp/bake time: A high temp (205°) gets you crispy edges and cooked centers without too flat of a spread. The longer the cookies are in the hot oven, the more they spread; high temp and shorter bake time > lower temp and longer bake time. (If your oven runs hot, try 375° first). Check the cookies at 8 minutes and bake 2-3 minutes longer as needed. Mine generally take 9-10 minutes.
Chocolate chips: I go for 1 cup (170g) chocolate chips, then press more into the tops of the cookies when they come out of the oven.
Mostly brown sugar + extra egg yolk = extra moist, gooey, chewy. Feel free to play around with the brown:white sugar ratio to suit your preferences. There’s 1 cup (200g) total sugar in the recipe.
Baking soda = chewy and browned, with crispy edges. Baking powder = soft, cakey.
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