1. Line a baking sheet with parchment paper, preparing your workstation for easy cleanup and setting.

2. Add the 5 cups of Rice Chex cereal to a large mixing bowl. Pour the ½ cup of powdered sugar into a 1-gallon zip-top bag and set aside.

3. Melt the 10 oz of white melting chocolate in a microwave-safe bowl. Heat in 30-second intervals, stirring thoroughly after each interval, until completely smooth and creamy. Be careful not to overheat to avoid seizing.

4. Pour the melted white chocolate over the Chex cereal in the large bowl. Using a spatula, gently stir until all the cereal is evenly coated with the chocolate, ensuring no dry spots remain.

5. Transfer half of the chocolate-coated cereal into the zip-top bag containing the powdered sugar. Seal the bag tightly and shake gently but thoroughly until the cereal is completely coated in sugar.

6. In the large bowl with the remaining chocolate-coated cereal, gently mix in the 1 cup of mini pretzels. This keeps them from getting overly coated in powdered sugar, maintaining texture contrast.

7. Spread the pretzel-and-cereal mix evenly onto the parchment-lined baking sheet.

8. Immediately sprinkle the 6 oz of Valentine’s M&Ms and the optional sprinkles over the mix on the baking sheet. Then, add the powdered sugar-coated cereal mixture on top, distributing it evenly.

9. Allow the puppy chow to sit undisturbed for at least 20 minutes to set. Once set, gently break apart any clumps and serve. Enjoy your festive, no-bake treat!