Cadbury has an ongoing promotional campaign employing the "Caramilk Secret" or "Secret of the Caramilk Bar". They make people wonder how they get the soft, flowing caramel into the chocolately pockets of the Caramilk bar. It's all cute and entertaining, but there's no mystery. Solid caramel drops are made by freezing fixed amounts of caramel syrup into a round shape. The chocolate portion of the bar is made in two halves (which explains the seam running around the bar's perimeter in its final form). The caramel drops are placed into the bottom chocolate half, and then the top chocolate half is placed on top, forming the whole bar. Then the bar is heated or allowed to naturally reach room temperature, at which point the caramel drops turn liquid.