Preheat oven to 350 degrees F. Line a 13x9 inch metal pan with non-stick foil or parchment paper.
Mix together flour, baking soda, salt and cinnamon; set aside.
Beat pureed bananas, sugar, eggs, oil, and vanilla together in a large mixing boil. Add flour mixture and stir until blended. Stir in pineapple, cherries and walnuts. Pour batter into pan and spread to edges.
Bake 30-35 minutes. Cool completely, and then frost with icing. Decorate with extra cherries and nuts if desired.
Icing: Combine butter and cream cheese and beat until fluffy. Add sugar, stir well and then beat until light. It’s best to use an electric mixer for this. Beat in vanilla. Add 1-2 tablespoons of milk and beat until light and fluffy. Ice bars.