Popcorn Cake
["8 c. freshly popped popcorn, unsalted", "3/4 c. sugar", "3/4 c. firmly packed brown sugar", "1/2 c. light corn syrup", "1 tsp. vinegar", "1 tsp. vanilla", "1/4 tsp. salt", "3/4 c. butter", "1 c. M&M's", "1 c. cashews", "1 c. miniature marshmallows"]
["Pop popcorn; set aside in large bowl.", "Combine next 6 ingredients in a large saucepan.", "Cook over medium heat, stirring frequently until mixture reaches hard ball stage (260\u00b0).", "Remove from heat; add butter, stirring until butter melts.", "Pour syrup in a thin stream over popcorn, stirring until popcorn is evenly coated.", "Stir in remaining ingredients, mixing well.", "Press mixture into a well-greased ring mold; cool.", "Unmold on serving plate."]
["freshly popped popcorn", "sugar", "brown sugar", "light corn syrup", "vinegar", "vanilla", "salt", "butter", "cashews", "marshmallows"]