- 3 ½ cups (17.5 ounces) all-purpose flour
- 1 ½ teaspoons baking powder
- 1 ¼ teaspoons baking soda
- 1 ½ teaspoons coarse sea salt, plus additional coarse flaky sea salt for sprinkling lightly on cookies
- 1 ½ cups unsalted butter, room temperature
- 1 ⅔ cups (11.5 ounces) light brown sugar, packed
- 1 cup (7 ounces) granulated sugar
- 2 eggs
- 1 teaspoon vanilla extract
- 5 (4-ounce) bars high-quality bittersweet chocolate, still in their wrappers
Whisk flour, baking powder, baking soda and coarse sea salt together in a large bowl. Set aside.
Combine the butter and the sugars. Beat on medium speed with an electric mixer until light and airy, about 4 minutes. Add the eggs one at a time, beating for 30 seconds after each addition to incorporate, and scraping down the sides of the bowl with a rubber spatula as necessary. Add the vanilla and whip for 30 more seconds to combine.
Add the flour mixture to the butter mixture and mix at low speed until just combined, about 30 seconds.
Using a heavy rolling pin or small skillet, repeatedly whack the chocolate bars (still in their wrappers) one at a time until they are broken into smaller chunks no larger than ½ inch. Unwrap the broken bars and add the broken chocolate, including smaller pieces and crumbs, to the dough bowl. When all five bars have been added to the bowl, mix on low speed until just combined, about 1 minute. The dough should end up looking light brown with larger chunks of chocolate dispersed throughout.
Cover dough and refrigerate until cold, at least 1 hour or overnight.
Adjust two oven racks to the upper middle and lower middle positions and preheat the oven to 350 F. Roll half the dough into twelve 1 ¾-inch balls, approximately 3 tablespoons of dough in each. Place the balls 3 inches apart on two parchment-lined cookie sheets, six cookies per sheet.
Bake the cookies for 8 minutes, until they are completely spread out. Remove them from the oven and sprinkle each cookie with sea salt.
Return the pans to the oven, rotating them from front to back and top to bottom. Continue baking until the cookies are golden around the edges but still soft in the centre, 6 to 8 minutes.
Cool for 3 minutes, then slide the parchment, along with the cookies, onto two cooling racks while you cook the remaining 12 cookies. To store the cookies, allow them to completely cool, then place in a covered container at room temperature for up to three days.