Line a baking sheet, large plate, or platter with parchment paper. Make sure it fits in your fridge or freezer before you start.
Add the maple syrup and butter to a medium saucepan. Warm over medium heat, whisking often, until melted and smooth.
Bring to a full rolling boil. Add the cocoa powder and let it bubble for exactly 60 seconds, stirring the whole time. Do not boil longer or the cookies can turn dry and crumbly.
Remove the pan from the heat immediately. Stir in the peanut butter, vanilla extract, and the optional pinch of salt until completely smooth.
Add the rolled oats to the saucepan and stir until fully coated.
While the mixture is still warm, drop 1 heaping tablespoon scoop or a cookie scooper of the mixture onto the parchment paper. Press down gently with the back of a fork to flatten into cookie shapes.
Freeze the cookies for about 20 minutes, or refrigerate them for 30 minutes, until firm.
