Grease and flour 10" tube pan. Melt butter in saucepan. Stir in frosting mix and rolled oats until crumbly. Blend sour cream, eggs and bananas in a bow until smooth. Blend in cake mix and beat 2 minutes at medium speed. Pour 1/3 of the batter into pan. Sprinkle with 1/3 of the crunch mix. Repeat twice. Bake at 350 degrees for 50 - 60 minutes. Remove from pan and invert cake so crunch mix is on the top. ENJOY!