8 ounces (2 sticks) unsalted butter
1 standard ice cube (about 2 tablespoons frozen water)
10 ounces (about 2 cups) all-purpose flour
3/4 teaspoon baking soda
2 teaspoons Diamond Crystal kosher salt or 1 teaspoon table salt
5 ounces (about 3/4 cup) granulated sugar
2 large eggs
2 teaspoons vanilla extract
5 ounces (about 1/2 tightly packed cup plus 2 tablespoons) dark brown sugar
8 ounces semi-sweet chocolate, roughly chopped with a knife into 1/2- to 1/4-inch chunks
Coarse sea salt for ganish