Line a sheet tray with parchment paper and set aside.
In a large bowl, mix together the peanut butter, vanilla, butter, coconut and cocoa powder. Stir well, making sure the batter is mixed completely.
Add the erythrtiol and stir again.
Scoop the cookie dough onto the prepared sheet tray, making scoops about 2 tablespoons in size.
Gently press the top of each cookie to flatten it slightly.
Place the tray in the freezer to let the cookies harden. They should be ready to eat in about 30 minutes! Store the cookies in an airtight container either in the fridge or in the freezer.