Beat together the peanut butter and sugar in a large mixing bowl, using a hand mixer. Stop when the mixture is creamy, about 2-3 minutes.
Add the egg and continue to mix for another minute until fully incorporated.
Using a tablespoon or regular spoon, scoop cookie dough and form into balls. Place them evenly on a parchment paper-lined cookie sheet, about 8 cookies per cookie sheet. Press each round down with a fork twice in the shape of a plus sign to form a pattern.
Bake the cookies for 10-12 minutes. Allow them to cool before serving.