Preheat your oven to 300°F (150°C) and line your baking sheet with parchment paper.
Place the white and pink candy melts on the parchment paper and spread them out into a single, even layer. Don't mix them up just yet—you want both colors to stay visible.
Carefully place the baking sheet in your preheated oven and bake for about 5 minutes. Keep a close eye on it; the chocolate should soften and start to melt, but it shouldn't bubble over.
Remove the baking sheet from the oven using oven mitts. With a fork, spatula, or chopstick, gently swirl the melted chocolate to create a marbled effect.
Quickly sprinkle the M&Ms, conversation hearts, and Valentine's sprinkles on top while the candy is still soft.
Place the baking sheet in the refrigerator for 30 minutes to let the bark harden. If you prefer, you can also let it cool at room temperature for about 1 hour.
Once the Valentine bark is firm, remove it from the baking sheet by lifting the parchment paper. Break it into pieces with your hands or a knife. Enjoy your Valentine's Day treat!
