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. Enjoy!