Into large mixing bowl, sift the flour, sugar, baking powder, baking soda and salt. Add the shortening, half cup mashed bananas and eggs. Beat mixture for 2 minutes at medium speed with an electric mixer. Scrape down bowl and beaters, then add the remaining 1 cup of mashed bananas and vanilla. Beat batter for -20ºC ull minute at medium speed. Pour batter into two greased and floured 20 cm round cake pans. Bake in a preheated oven at 190ºC or 25 minutes or until a toothpick inserted in center of layer comes out clean. Cool in pans on a wire rack for 10 minutes. Remove from pans. Return layers to wire racks. Cool completely. Frost.
Banana Frosting: Cream margarine with electric mixer, then add half of the confectioners sugar and beat well. Blend in lemon juice and bananas, then add remaining sugar and beat well.