Begin by preheating your oven to 275 degrees and line a large baking sheet with parchment paper or foil..
In a large bowl toss together the Chex cereals, mini pretzels, Cheez-Its, peanuts and set aside
In a small bowl mix together the melted butter, brown sugar, honey or maple syrup, kosher salt, and cinnamon.
Pour this mixture over the snack mix and stir evenly to coat as best you can, spreading as you stir. (use two sheet pans if necessary, depends on how many cups cereal etc you use...and you can adjust cereals of your choice)
Bake for about 25 minutes or until cereals appear to be crisping up. (Check after 15 minutes to be sure the mixture is not burning, stir to re-mix then continue to bake for about 10 minutes more.) Total time should be about 25 minutes.
Remove from the oven and allow cereal mix to cool at room temperature. when cool, add in the mini marshmallows, candy corn and Reece's Pieces.
Store in airtight container.
Notes
You can add your favorite ingredients or substitute any of the cereals. This retro recipe is very flexible just like the original Chex party mixes.