In a medium bowl, place blackberries and honey and smash with a fork until desired consistency (I like to leave some blackberry chunks).
In a separate bowl, mix together milk, vanilla, beaten and cinnamon.
Spread 1-2 tablespoons of blackberries on one slice of bread.
Spread 1 tablespoon peanut butter on another slice of bread.
Form a sandwich and carefully dip into extra mixture on both sides.
Place tablespoon of butter in skillet and grill until golden brown.
Flip over and cook the other side.
Follow the same instructions for the second sandwich.