10 ounces dark chocolate, roughly chopped (see notes)
Instructions
In a medium bowl, whisk together the flours, baking powder, baking soda and salt.
In the bowl of a stand mixer fitted with a paddle attachment, or in a bowl with a hand-held mixer, beat the butter and sugars at medium speed until well blended. Add the egg and vanilla extract and continue to beat until well blended.
Gradually add the dry ingredients and beat on low speed until just combined. Add the chocolate and stir to combine.
Turn the dough out onto a piece of plastic wrap and pat into a square about 1" thick. Wrap dough and chill for at least 24 hours or up to 3 days.
When you're ready to bake the cookies, preheat oven to 350 degrees. Line two baking sheets with parchment paper.
Divide dough into 12 equal pieces and shape each piece into a ball. Place the balls on the prepared baking sheets about 3 inches apart. Sprinkle balls with sea salt.
Bake cookies, one sheet at a time, until the tops are lightly golden and the centers are still soft, 15-18 minutes.
Remove from the oven and allow cookies to rest on the baking sheet for 10 minutes before transferring to a wire rack.