Heat oven to 250°F. Line a baking sheet with parchment paper.

In a large bowl, combine the Cherrios, peanuts, and raisins.

In a large pot, heat the brown sugar, butter, corn syrup, and salt over medium heat until bubbly around the edges. Cook uncovered for 2 minutes, stirring once.

Remove from the heat and stir in baking soda. Immediately pour over the cereal mixture in the bowl. Then spread it out on the prepared baking sheet. Bake for 20 minutes stirring once half way through.

Right when you take it out of the oven, spread the M&Ms over the top. Let stand for 10 minutes, then break into pieces.