1stick plus 3 tablespoons11 tablespoons unsalted butter, at room temperature
2/3cuppacked light brown sugar
1/4cupsugar
1/2teaspoonfleur de sel or 1/4 teaspoon fine sea salt
1teaspoonvanilla extract
5ouncesbittersweet chocolatechopped into chips, or a generous 3/4 cup store-bought mini chocolate chips
Instructions
Whisk flour, cocoa powder, and baking soda into medium bowl.
Using electric mixer, beat butter in large bowl until smooth and creamy. Add both sugars, vanilla, and sea salt; beat until fluffy, about 2 minutes. Add flour mixture; beat gently just until blended (mixture may be crumbly). Add chopped chocolate; mix just to distribute (if dough doesn’t come together, knead lightly in bowl to form ball). Divide dough in half. Place each half on a sheet of plastic wrap or parchment. Form each piece into 1 1/2-inch-diameter log. Wrap each tightly and chill until firm, about 3 hours. (Note: this can be done in advance – logs can be stored in the fridge up to three days before slicing and baking).
Preheat oven to 325°F. Line baking sheets with parchment paper. Using a sharp knife, cut logs crosswise into 1/2-inch-thick rounds. Space cookies 1 inch apart on prepared sheets. Bake 1 sheet at a time until cookies appear dry (cookies will not be firm or golden at edges), exactly 12 minutes. Transfer to rack and cool before enjoying with a large glass of milk.