Preheat oven to 350ºF (180ºC).
In a large bowl, mix together the peanut butter, sugar, and egg.
Scoop out a spoonful of dough and roll it into a ball.
Place the cookie balls onto a nonstick baking sheet.
For extra decoration and to make them cook more evenly, flatten the cookie balls by pressing a fork down on top of them, then press it down again at a 90º angle to make a criss-cross pattern.
Bake for 8-10 minutes or until the bottom of the cookies are golden brown.
Remove from baking sheet and cool.