Preheat your oven to 350ºF (180ºC) and line your baking sheet with a silicon mat or parchment paper.
In a bowl, combine peanut butter, sugar and eggs and mix very well with a fork or spatula, until everything is combined and you get a dough with a thick consistency. If you are adding mix-ins, add them now.
Portion little balls of 20 grams (triple the recipe to make them bigger)and place over your prepared baking sheet.
Flatten each ball lightly by pressing with a fork.
Bake in a preheated oven for 8 minutes (if you are making bigger cookies you might need to adjust your baking time)
The cookies are done when they are firm to the touch and, lightly brown at the bottom and have a matte finish.