Mix peanut butter, sugar, and egg in a mixing bowl with a hand mixer until well combined.
Roll 1 tbsp of mixture into a ball and place on the parchment paper on a baking tray. Repeat until all the mixture is on the baking tray.
Using a fork, create a hatch like pattern on each ball by pressing down on them twice in 90-degree orientation.
Push 3 pieces of raisins into each cookie.
Bake in a pre-heated oven at 350 degrees F for about 30 minutes.
Take the tray out of the oven and let it cool completely.