Preheat oven to 350 degrees F (175 degrees C). Line a baking sheet with parchment paper.

Using an electric mixer or a strong spoon, mix together the peanut butter, white sugar and egg until smooth.

Form dough into round tablespoon-fulls. Then roll in an extra bowl of sugar, if desired, to coat the outside of the dough ball. Place on the baking sheet at least 2 inches apart, and then use a fork to flatten and form a cross pattern.

Bake for 6 to 8 minutes, until the cookies are just slightly browned on the botton, being careful not to over-bake. Remove and let cool on the baking sheet for 1 minute, then transfer to a wire rack to cool completely.