In a large mixing bowl, add the dry ingredients and mix well. In a microwave safe bowl, add the peanut butter and maple syrup. Microwave until the peanut butter has melted, and whisk well until combined.
Transfer the wet mixture into the dry ingredients and mix well, until a thick batter remains. Using your hands, form 12 balls of dough and place them on the lined plate. Press down into a cookie shape and using a fork, cross each side.
Place the plate in the refrigerator for at least an hour, for the cookies to firm up.
TO STORE: Cookies should always be stored in the refrigerator, covered, so they remain thick and firm. The cookies will keep well for at least 2 weeks.TO FREEZE: Place cookies in a ziplock bag and store them in the freezer for up to 6 months.