1. Preheat oven to 350F (175C). line a baking tray with a parchment paper.
2. In a large bowl mix peanut butter, sugar and egg.
3. Roll into 16 small balls. place then onto prepared baking sheet. Flatten each ball with a fork, making a crisscross pattern.
4. Bake for 8-10 minutes, until cookies begin to brown. Transfer to a cooling rack and Let cool.