Fourth of July Popcorn Cake

1 (16 ounce) package miniature marshmallows
20 caramels
1/4 cup butter, cubed
10 cups popped popcorn
1 1/2 cups salted peanuts
1 cup red, white and blue milk chocolate M&M's

In a microwave-safe bowl, combine the marshmallows, caramels and butter. Microwave, uncovered, on high for 3 minutes or until melted, stirring occasionally. Place the popcorn in a large bowl; pour caramel mixture over popcorn and mix well. Stir in peanuts and M&M's. Press into a well-greased 10-incg tube pan. Cool until firm. Remove from pan; cut with a serrated knife.