Preheat the oven to 350°F
Line a large baking sheet with nonstick cooking paper or parchment.
Add the egg and sugar to a bowl and whisk vigorously until combined and pale yellow in color.
Add the peanut butter, and use a fork to thoroughly combine it. This takes a few minutes, so be patient. It needs to thoroughly mixed.
Place the cookie batter into the refrigerator for 15 minutes.
Using a tablespoon, place scoops of the batter on your prepared baking sheet, about an inch and a half apart.
After your pan is filled, gently roll each cookie into a ball and dip the top in the sugar.
If desired, use a fork to make the classic crisscross design on top.
Bake for 9 to 11 minutes, or until the edges start to look dry.
Remove them from the oven and allow them to cool for at least five minutes. Drag the paper onto the counter, leaving the cookies in place. Allow them to cool completely before removing them from the paper, about 10 more minutes. They should come off easily.
Store in an air-tight container for up to five days - if they last that long ;)