Finely chop kale and set aside. In a microwave –safe bowl, combine marshmallows, caramels, and butter. Microwave, uncovered, on high for 3 minutes or until melted, stirring occasionally. Combine kale, popcorn, cashews, and M&M's in a large glass bowl. Pour caramel mixture over kale mixture and mix well. Press into a prepared 10-inch tube pan. Cool until firm. Remove from pan; cut into pieces.