Preheat oven to 350°F (177°C). Line two large cookie sheets with parchment paper or silicone baking mats.
Add peanut butter, whisked egg and maple syrup into a large mixing bowl. Stir with a spatula until maple syrup and egg are completely incorporated into the peanut butter and your mixture begins to thicken to a cookie dough consistency.
Using a 1 tbsp cookie scoop, scoop dough and place onto a prepared cookie sheet, spacing the dough about 2 inches apart. Press down on each dough ball with the palm of your hand so that it forms a thick round disk. Don't flatten the dough fully because it will get flattened more when you make the criss-cross pattern. Use a fork to make a criss-cross pattern on the surface of each cookie.
Bake cookies for about 10 minutes. Cookies should crack slightly during baking and look dry on the surface when done. Let cookies fully cool on baking sheet before removing.
Notes
Make sure to use natural peanut butter that has no added oils. This recipe will not work with the same with regular peanut butter.
This recipe works best with pure maple syrup. Honey changes the texture of the cookies.
You don't have to make the criss-cross pattern across the surface, but if you choose to leave it off, then flatten your cookies a little more to the thickness you want the final outcome to be before baking.
You can halve the recipe if you want to make less but you will need to make sure you only add half a whisked egg. If you add a full egg, the cookies will turn out oily and have a gummy texture.
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.