Prep Your Station. Spread out a few sheets of parchment paper (I like to put mine on a baking sheet for stability, but feel free to spread the parchment out on your counter).
Combine The Valentines Chex Mix Ingredients. Set aside half of the M&Ms to decorate with at the end. In your largest large bowl, combine rice Chex, corn Chex, Cheerios, gluten-free pretzels, half of the m&ms, and the peanuts (if using).
Melt The White Chocolate Coating. In a microwave-safe bowl, melt vanilla almond bark in 20-30 second intervals, stirring well after each interval until the white chocolate coating is smooth and has no lumps. (You can also do this on the stovetop in a double boiler, if you prefer)
Drizzle & Stir. Pour the melted vanilla bark/candy melts over the cereal mixture and quickly stir to combine. (You want to coat everything well with the white chocolate mixture, but work quickly since the candy melts will start to cool and harden.)
Spread Out, Sprinkle & Cool. Transfer the coated cereal onto your prepared sheets of parchment, and immediately sprinkle on the second half of the Valentines m&ms and the sprinkles (if using), and let it cool to set. It will form some clusters as it cools. I like to leave some larger sections and some smaller sections rather than breaking it all up.
Serve & Store. Once the chocolate is all set, enjoy it right away, or transfer to an airtight container and store at room temperature on the counter up to 1 week.