Preheat your oven to 350°F (175°C).

Line a baking sheet with either parchment paper or a silicone mat.

In a large bowl, mix the peanut butter, sugar, and room temperature egg together. Use a fork, whisk, stand mixer, or electric mixer to mix until all the ingredients are well combined and a thick dough has formed. 

Using a cookie scoop or a measuring spoon, scoop tablespoon-sized portions of the dough and roll them into balls using the palm of your hands. 

Place the cookie dough balls on the baking sheet that you prepared, leaving about 2 inches of space between them.

Use the back of a fork to create a criss-cross pattern on the cookies if you want. The fork marks are optional. 

Bake the cookies in the preheated oven for 10 to 15 minutes or until the edges are lightly golden. 

Remove the cookie sheet from the oven and let the cookies cool on the sheet for 5 minutes.

Transfer them to a wire rack so they can cool completely.