Preheat oven to 300°F (150°C). Prepare popcorn according to package directions. In large 4 qt (3.8 L) Plastic Mixing Bowl, combine popcorn, pretzels, peanuts and cereal; set aside. Combine butter, brown sugar and corn syrup in 2-qt. (1.9 L) Brilliance Nonstick Sauce Pan. Cook and stir over medium heat until mixture comes to a boil. Continue to cook without stirring 3 minutes. Remove from heat; carefully stir in baking soda.
Pour caramel sauce over popcorn mixture; stir until evenly coated. Spoon onto Stone Bar Pan; bake 30 minutes, stirring occasionally. Remove from oven.
Transfer popcorn mixture to large piece of parchment paper. Cool completely, breaking mixture into clusters as it cools.