Salty Sweet Muddy Buddies

Measure out Chex and pretzels into a large bowl; stir and set aside. In a microwave-safe bowl, combine chocolate chips, peanut butter and butter. Microwave on high for 1 minute; stir. If mixture isn’t smooth, microwave for another 30 seconds. Add vanilla and salt, if using; stir. Pour over cereal and mix until cereal and pretzels are evenly coated. Spoon half of the cereal mixture into a large Ziploc bag. Add half the powdered sugar and shake until coated. Repeat with the second half. Stir in M&Ms. Store in an airtight container.