Instructions In a large bowl combine the corn chex, rice chex, whole wheat chex, pretzels, popcorn and nuts. Toss well. In a small bowl whisk together the melted butter, cinnamon and vanilla. Pour the butter mixture over the chex mix and toss well with you hands until the butter and cinnamon has coated all of the chex mix. Using cooking spray or canola oil thoroughly grease 24 cupcake molds (or for bars grease or line with wax paper a 9x13 inch pan), set aside, Add the Karo syrup, peanut butter and brown sugar together in medium saucepan. Heat almost to a boil but be careful not to burn. Stir to combine the ingredients. Once the mixture begins to bubble around the edges, stir for 1 minute and then remove from the heat. Pour the peanut butter mixture over the chex mix and toss well with a spatula. Spoon the mixture evenly among 24 cupcake mold, or one 9x13 inch pyrex dish, and lightly press the mixture together. Melt the chocolate chips in the microwave or over a double broiler. I like to microwave mine, heating on full power for 20 seconds, stir, 30 seconds again, and stir until melted. Spoon a tablespoon or so of melted chocolate over each bar. Place the trays in the fridge for 45 minutes or until ready serve. Once ready to serve use a butter knife to pop the bars up and out of their molds.