How to Make It
Combine the flour and baking soda in a small bowl. In a large bowl, combine the sugars and butter and beat on medium speed until well blended. Add the vanilla and 1 egg and blend again. Slowly sift the flour mixture into the butter mixture, working the dough just until it comes together. Add half the peanuts and stir to combine. Press the dough into a disc, cover with plastic wrap, and chill for 15 minutes.
Heat oven to 325°F and spray a large baking sheet with nonstick cooking spray. Dust your hands with flour and press the chilled dough into the cookie sheet, spreading it towards the edges of the pan until it is as thin as you can get it without tearing the dough. Beat the remaining egg and brush it over the surface of the dough. Sprinkle the remaining peanuts over the dough, pressing down with your fingertips so that the nuts adhere.
Bake for 25 minutes or until fragrant and dark brown. Let the dough cool in pan for 5 minutes, then break it into rough “shards” and transfer to a wire rack to cool completely.