In a large bowl, combine the 3 cups Chex, 2 cups Cheerios, 1-2 cups pretzels, 1 cup candy corn, and 1 cup M&M's. Stir until everything is mixed well. The colors and textures should stand out beautifully in the bowl.
Place 10 ounces white chocolate in a microwave-safe bowl. Microwave the chocolate at 50% power for one minute. Stir the chocolate and continue to melt in 30-second increments, stirring in between. Be careful not to overcook it, as this can lead to burnt chocolate.
Once melted, pour the chocolate over the Chex mix. Stir until every piece is well coated with the creamy chocolate. Then, pour the mixture onto a piece of wax or parchment paper. For a festive touch, sprinkle extra M&M's and Halloween sprinkles on top while the chocolate is still warm.
Allow the mix to set until hardened, which should take at least 15 minutes. Once done, you can store it in a zip-top bag or covered container. It’ll stay fresh on the counter for about three days or can be frozen for up to three months.
