Mix in the M & M's, pretzels, and peanuts. Spread out on a large jelly roll pan (or cookie sheet).
Place white chocolate chips and shortening into a microwave-safe bowl.
Cook for 45 seconds, remove from microwave, and stir. Continue cooking at 25 second intervals, stirring each time, until chocolate is completely melted and smooth.
Drizzle chocolate over popcorn mixture and gently mix until most pieces are covered with chocolate.
Notes
While sometimes its nice to keep it simple, feel free to try some of these tasty ideas, too! Some add-ins we like include the following: Oreo pieces, peanut butter M&Ms, Andes mint pieces, dried cranberries, cashews, Nestle's Crunch Bar pieces, and Reese's Pieces.