¾cup(2.25 ounces) Dutch-processed or black cocoa powder
1cup(8 ounces) unsalted butter, at room temperature
1cup(7 ounces) granulated sugar
1cuptightly packed, (7.5 ounces) dark brown sugar
1 ½teaspoonspure vanilla extract
¾cup(4.5 ounces) dark chocolate chips (I used Nestlé Toll House Artisan Collection Extra Dark Premium Baking Chips), plus more for finishing
¾cup(4.5 ounces) milk chocolate chips (I used Guittard Milk Chocolate Organic Wafers), plus more for finishing
¾cup(4.5 ounces) white chocolate chips (I used Valrhona Dulcey Chocolate Feves), plus more for finishing
flaky sea salt, for garnish
Position a rack in the center of the oven and preheat the oven to 350°F. Line two half sheet pans with parchment paper.
In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt.
In the bowl of a stand mixer fitted with the paddle attachment, combine the butter and sugars. Beat on medium-high until light, fluffy, and doubled in volume, 3 to 5 minutes. Reduce the mixer to low and add the eggs and vanilla; beat until just combined. Use a rubber spatula to scrape down the bottom and sides of the bowl. With the mixer on low, gradually add the dry ingredients and beat until just combined. Scrape down the bottom and sides of the bowl once more, and beat on low for an additional 30 seconds. Increase the mixer to medium- low, add the chocolates all at once, and beat until the chocolate is evenly distributed throughout, about 1 minute.
Use a 3-tablespoon cookie dough scoop to portion the cookie dough into balls, placing them at least 3 inches apart on the prepared sheet pans. Gently press 4 to 5 different chocolate chips on top of each dough ball.
Bake one pan at a time for 12 minutes, or until the edges have set but the centers are still gooey. The cookies will look puffed when you pull them out of the oven, but will fall and crack into the perfect cookies as they cool. Cool the cookies completely on the pan on a wire rack. Repeat with the remaining cookie dough (or freeze it to bake later). Serve warm or at room temperature. The cookies can be stored in an airtight container or zip-top bag at room temperature for up to 3 days.