-cake mix Heat oven to 180ºC F. Grease and flour 25 cm tube pan. Lightly spoon flour into measuring cup; level off. In medium bowl, combine flour, coconut, rolled oats, brown sugar and pecans; mix well. Using fork or pastry blender, cut in margarine until mixture is crumbly; set aside. In large bowl, combine bananas, sour cream and eggs; blend until smooth. Add cake mix; beat 2 minutes at high speed. Spread one third of batter in greased and floured pan; sprinkle with one third of coconut mixture. Repeat layers twice using remaining batter and coconut mixture, ending with coconut mixture. Bake for 50-60 minutes or until toothpick inserted near center comes out clean. Cool upright in pan 15 minutes; remove from pan. Place on serving plate, coconut side up. Cool completely.