Preheat oven to 300 degrees F. Line 1-2 large rimmed jelly roll sheet with parchment paper.
In an extra large mixing bowl, combine rice cereal, peanuts, pretzels, cheese crackers, sesame sticks, and oyster crackers.
Gently toss with large slotted spoons.
Melt butter in microwave and toss together with mixture in bowl.
Combine Italian seasoning, ranch seasoning powder, mustard powder, grated parmesan, and dried parsley.
Save 1 tablespoon of the mixture; set aside.
Sprinkle the remaining mixture over the top of the bowl then gently toss everything together.
Pour mixture evenly over prepared pan.
Bake in oven 30 minutes, tossing mixture halfway through baking.
Sprinkle 1 tablespoon seasoning mixture of the top. Garnish with extra grated parmesan cheese and dried parsley.
Allow to cool then store in airtight container.
*This Italian Chex Mix tastes best when at room temperature.