Holding one end of the graham cracker, dip the bottom into the melted white chocolate. Use a spatula to gently tap the white chocolate along the sides until the graham cracker is sufficiently covered. Lift the graham cracker out of the white chocolate and use the spatula to slide down the flat sides of the graham cracker, smoothing the candy coating and removing any excess. Give the graham cracker a quick, final shake, then place on parchment paper to dry. Sprinkle tops of graham crackers with ground cinnamon (optional). Repeat this step until all graham crackers are coated.