I made a few modifications to this recipe on Epicurious. I didn't use as much salt, so these cookies were more like regular chocolate chip instead of salty chocolate chip. It didn't matter, though. They were delicious! I enjoyed them soft and warm out of the oven, but they were even better slightly crispy the next day (perfect make-ahead cookie!). I was really intrigued by the powdered sugar included in the ingredients list and think it made the cookies a little softer and sweeter.
1 1/2 cups all-purpose flour
1 teaspoon baking powder
1/2 teaspoon kosher salt
1/4 teaspoon baking soda
1/2 cup (1 stick) unsalted butter, room temperature
3/4 cup (packed) light brown sugar
1/2 cup sugar
1/4 cup powdered sugar
2 large egg yolks
1 large egg
1 teaspoon vanilla extract
8 ounces semisweet or bittersweet chocolate (do not exceed 72% cacao), coarsely chopped
Place racks in upper and lower thirds of oven and preheat to 375°F. Whisk flour, baking powder, kosher salt, and baking soda in a medium bowl; set aside.
Using an electric mixer on medium speed, beat butter, brown sugar, sugar, and powdered sugar until light and fluffy, 3-4 minutes. Add egg yolks, egg, and vanilla. Beat, occasionally scraping down the sides of the bowl, until mixture is pale and fluffy, 4-5 minutes. Reduce mixer speed to low; slowly add dry ingredients, mixing just to blend. Using a spatula, fold in chocolate.
Spoon rounded tablespoonfuls of cookie dough onto 2 parchment paper-lined baking sheets, spacing 1" apart. Sprinkle cookies with sea salt.
Bake cookies, rotating sheets halfway through, until just golden brown around the edges, 10-12 minutes (the cookies will firm up as they cool). Let cool slightly on baking sheets, then transfer to wire racks; let cool completely.
Yields 3 dozen