MICROWAVE each package of chocolate in separate medium microwaveable bowl on HIGH 2 min. or until almost melted, stirring after each minute until completely melted.
STIR red food coloring into 1 bowl of chocolate until blended. Alternately spoon the chocolates onto waxed paper-covered baking sheet. Tap baking sheet on table to evenly disperse the chocolates. Swirl with knife for marble effect.
REFRIGERATE 1 hour or until firm. Break into pieces.