1. Line a quarter sheet tray or rimmed baking sheet with aluminum foil.
2. Place the white chocolate in a large, heatproof bowl, and microwave at 15-second increments, stirring between each, until fully melted.
3. Pour about a third of the chocolate into a smaller bowl. Sift the red velvet cake mix into the larger portion and sprinkle with the powdered food color. Stir together until mixed completely. Add more coloring bit by bit until you achieve the desired color.
4. Working quickly, pour the red mixture on to the prepared tray, and spread into an even layer about ¼-½ inch thick (it may not cover the entire tray.) Immediately pour the reserved white chocolate in a swirl over the pink chocolate. Using a toothpick, drag lines through the chocolate to create a marbled pattern. Immediately scatter the candy on top and allow the chocolate to set for 30 minutes in the fridge.
5. When ready, use the foil to carefully lift the bark from the tray. Flip over onto a plate, and give it a whack with a wooden spoon on the smooth, aluminum foiled side. The bark will release in shards. Enjoy.