In a mixing bowl, beat together the egg, granulated sugar, baking powder and vanilla extract for almost a minute.
Add the peanut butter followed by the water and beat together. If you notice the mixture is not coming together or is crumbly, you can add another teaspoon of water.
Using a cookie scoop, add the peanut butter dough to a baking sheet that's been lined with parchment paper.
Then using a fork, make indentations into each cookie.
Bake for 12 to 15 minutes until the cookies feel firm and are slightly browned.
Allow the cookies to cool on the baking tray for a minute or two and then gently transfer them to a cooling rack to cool completely.
Notes
If you find the fork sticking while making the indentations, you can either spray the fork with non-stick cooking spray or dip the fork in sugar.
Depending on the size of the cookie scoop you use, you should be able to get 12 to 15 cookies. I used a large cookie scoop and was able to get 12 cookies.