Preheat oven to 325°F (163°C). Line a large baking sheet with parchment paper or a silicone baking mat.
Add all ingredients into a large mixing bowl. Whisk until uniform. There should not be any streaks of egg white or clumps of powdered sugar remaining. The batter will be thick and sticky.
Using a 1 tbsp cookie scoop, scoop mixture and release onto prepared baking sheet, spacing cookies two inches apart. (I fill my cookie scoop slightly over 1 tbsp because some of the batter is going to stick to the scoop). The batter should look like round dollops on the baking sheet and the batter should be thick enough that the dollops don't spread much. Try your best to keep the dollops as round circles on the baking sheet. If some of your dollops are not round, you can reshape them the edge of a metal spoon. You do not need to smooth the surface of the dollops.
Bake the cookies for about 12 minutes. When cookies are done, the tops should be puffed and cracked. Let cookies fully cool before removing them from baking sheet. Use a thin cookie spatula to remove cookies because they do stick a little to the pan. Cookies can be enjoyed as soon as they are cooled. Uneaten cookies can be stored in an airtight container for a few days at room temperature.
Notes
You can double the recipe to make more cookies.
Make sure to use natural peanut butter. There should only be salt and peanuts in the ingredient list.
If your powdered sugar is clumpy, make sure to break up the clumps before measuring or using, otherwise you will have clumps in your batter. I usually put a whisk into my powdered sugar container and stir to break up any lumps.
When measuring out the powdered sugar, spoon it into the measuring cup and level off the top with a knife. Do not scoop the measuring cup into the powdered sugar because this will result in too much powdered sugar for the recipe.
You do need the extra 1 tbsp of powdered sugar. Without it, the cookies won't crack on top.
If you are making your own powdered sugar, make sure it has cornstarch included.
You do not need to smooth the surface of the cookies or spread out the batter before baking. But I do recommend trying to keep them round so that they turn out round when they are done baking.
The dough is quite sticky. If you find it difficult to release using the cookie scoop, you can use another spoon to release the batter.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.