Buckwheat Chocolate Chip Cookies

Name: Buckwheat Chocolate Chip Cookies
Prep time: 10 min
Cook time: 10 min
Total time: 20 min
Cuisine: American
Ingredients: 4 ounces unsalted butter, melted and kept warm ((1 stick) ); 1/2 cup plus 2 tablespoons buckwheat flour ((3 ounces) ); 1/4 cup all-purpose flour ((1 1/4 ounces) ); 1/4 cup whole spelt (or whole wheat pastry) flour ((1 ounce) ); 1/2 teaspoon baking soda; 1/2 teaspoon sea or kosher salt; 1/4 cup plus 2 tablespoons packed light brown sugar ((2 3/4 ounces) ); 1/4 cup granulated sugar ((1 3/4 ounces) ); 1 egg; 3/4 teaspoon vanilla extract; 1 cup coarsely chopped bittersweet chocolate (60 - 70% cacao mass) ((5 ounces) ); 1/2 cup walnuts toasted, cooled, skins rubbed off, and broken up or coarsely chopped (optional); 2 tablespoons cacao nibs (optional)