Line a large plate or tray with parchment paper and set aside.
In a microwave-safe bowl or in a small saucepan over low heat, combine the peanut butter and keto maple syrup; heat briefly until the mixture is smooth and pourable, stirring to combine.
Add the coconut flour to the peanut butter mixture and stir until a thick, cohesive batter forms.
Using clean hands, form small balls from the batter and place them on the prepared tray.
Press each ball flat to form a cookie, then use a fork to make a crosshatch pattern on top of each cookie.
Refrigerate the cookies until firm and fudgy, about 15–30 minutes, then serve.