Bake the cookies
Preheat the oven to 350 degrees F. Line the bottoms of two 12-by-18-inch sheet pans with parchment paper.
In a large bowl, stir the peanut butter, sugar, egg, baking soda and kosher salt until combined.
Stir in the chocolate and peanuts.
Using a small, greased ice cream scoop, measure out the dough in teaspoon sized balls.
Place the dough on the prepared pans, spacing them 2 inches apart.
Bake on the middle shelves of the oven, rotating the pans 180 degrees halfway through the baking time, until lightly golden and spread to a puffy mound, about 12-14 minutes.
Sprinkle lightly with fleur de sel.
Let cool completely on the pans on wire racks.
Store in an airtight container at room temperature for up to week.
Look for an organic peanut butter where peanuts are the only ingredient listed. These nut butters contain no added sugar and have a great mouthfeel. The peanuts used are generally of higher quality and have been roasted darker for a rich flavor.
Make sure to use a fleur de sel rather than a grey sea salt. Fleur de sel is an unprocessed salt, hand raked and harvested from the premium, top layers of salt beds in France. Fleur de sel; translates to; flower of salt; which refers to the scent of violets the salt develops as it bleaches and dries in the sun. The flavor, like the aroma, is more floral and less briny than other sea salts.