Instructions:
- Preheat oven to 250°F (120°C). Line baking sheets with parchment paper if desired.
- In a very large mixing bowl, gently combine all cereals, pretzels, and bagel chips/oyster crackers.
- In a small saucepan, melt the butter over low heat. Once melted, whisk in the Worcestershire sauce, seasoning salt, onion powder, garlic powder, thyme, and smoked paprika. If using, whisk in the brown sugar until dissolved.
- Pour about two-thirds of the melted butter mixture evenly over the cereal base. Gently toss everything until lightly coated. Add the remaining butter mixture, tossing again to ensure even coverage without crushing the cereal.
- Spread the entire mix in a single, thin layer across the prepared baking sheet(s).
- Bake for 15 minutes. Remove the pan from the oven, gently stir the mix thoroughly, and return to the oven. Repeat this stirring and baking process every 15 minutes for a total of 1 hour 15 minutes (Low and slow is the key to ultimate crispness!).
- Remove the mix from the oven. Let it cool completely on the baking sheet without touching it, as the crispness develops during cooling.
- Once cool, transfer to an airtight container for storage.