Combine the butter, brown and granulated sugars, vanilla extract, salt, baking powder, baking soda and nutmeg in the bowl of a stand mixer fitted with a paddle attachment. Mix on low to moisten, then increase the speed to medium and beat until soft, fluffy and pale, about 8 minutes; halfway through, pause to scrape down the bowl and beater with a flexible spatula. With the mixer running, add the eggs one at a time, letting each incorporate fully before adding the next. Reduce the speed to low, then add the flour all at once. When the flour is incorporated, add the chocolate chips and nuts and keep mixing until the dough is homogeneous.

Divide the dough into 8 equal portions (about 6 ounces/170 grams each) and round each into a smooth ball. Wrap in plastic and refrigerate for at least 12 hours before baking; if well protected from air, the dough can be kept in the fridge up to 1 week.

Adjust an oven rack to the middle position and preheat the oven to 350 degrees. Line 2 baking sheets with parchment paper. When the oven comes to temperature, arrange up to 4 portions of cold dough on the prepared pans, leaving ample space between them to account for spread. If you like, sprinkle with additional salt to taste.

Bake, 1 sheet at a time, for about 22 minutes, until the cookies are puffed and lightly brown or to an internal temperature of between 175 and 185 degrees. The ideal temperature will vary from person to person; future rounds can be baked more or less to achieve the desired consistency.

Cool the cookies directly on the baking sheet until no warmer than 100 degrees (they should feel lukewarm) before serving. Enjoy warm, or within 12 hours; these cookies taste best when freshly baked.