Preheat oven to 350 degrees F. Line a large baking sheet with parchment paper or a Silpat baking mat. Set aside.
In a large bowl, mix peanut butter, sugar, and egg together using an electric mixer or spatula. Mix until creamy and smooth.
Scoop the cookie dough into balls, about 1 tablespoon per cookie, and place on prepared baking sheet. Flatten each ball with the back of a fork, making a criss-cross pattern. The cookies don’t spread in the oven, so you can put them close together on the baking sheet.
Bake for 8 to 10 minutes or until edges are slightly golden. Don’t over bake. Remove from the oven and let the cookies cool on the baking sheet for 3 minutes. Transfer to a cooling rack to cool completely.
Notes
Store the cooled cookies in an airtight container on the counter for up to 4 days. You can also freeze the cookies for up to 3 months.