Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a medium bowl, combine the protein powder, peanut butter, and maple syrup; mix until well combined.

Add milk one tablespoon at a time until the mixture forms a workable dough that is not too sticky.

Roll the dough into 12 equally sized balls, flatten them slightly, and place them on the prepared baking sheet.

Bake for 10-12 minutes, or until the edges are lightly golden and the cookies are set. Let cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.