Mix the cereal, pretzels, Cheetos, and Cheez-Its in a large mixing bowl. Gently toss until well mixed.
In a microwave-safe bowl, melt the butter with the remaining ingredients. Whisk until the seasonings have dissolved. Pour over the party mix and gently toss to coat.
Spread the party mix evenly on an extra-large baking pan or 2 large baking pans and bake for 1 hour 15 minutes, stopping to stir every 15 minutes.
Spread on parchment paper to cool completely and store in an airtight container at room temperature.
Recipe Tips
Pro Tips for Perfect Cheesy Chex Mix
Do not skip the stirring. Stirring every 15 minutes is what produces an evenly coated, consistently crunchy result. Skipped stirs leave soggy patches where butter has pooled and dry patches where the seasoning never reached.
Spread in a genuine single layer. Pieces piled too deep steam rather than toast, which softens their texture. Use two baking sheets rather than crowding one.
Cool completely before storing. Sealing the mix in a container while it is still warm traps moisture and softens the crunch within hours.
If your oven runs hot, check the mix at the 45-minute mark. If it is browning faster than expected, reduce the temperature by 10 to 15 degrees.