Banana Chocolate Chip Cake
Preheat oven to 350ºF (180ºC).
Grease 13-x 9-inch (3.5 L) metal cake pan; line bottom with waxed paper. In bowl, beat bananas with sour cream until smooth; beat in eggs, then orange rind and vanilla. In large bowl, whisk together flour, sugar, baking powder, baking soda and salt; beat in butter and half of the banana mixture.
Beat in remaining banana mixture; stir in chocolate chips. Spread in pan; bake in centre of oven until tester inserter in centre comes out clean, 40 to 45 minutes. Let cool in pan on rack for 20 minutes. Run knife around edges of cake; invert onto rack and peel off paper. Invert onto another rack; let cool.
Combine icing ingredients in a large mixing bowl. Spread over cooled birthday cake.