Whitened walls and bottom of a deep rectangular baking dish. In a large bowl mix the flour, sugar, baking powder and baking soda. Crumpled add mashed bananas, cream, butter and vanilla macerate. Beat with a mixer until a homogeneous mixture and then add the eggs. Stir another 1-2 minutes. Add the crushed pieces of chocolate, which so far have kept in the refrigerator. Pour the mixture (with a density of cake batter) into the prepared form and smoothing top. Bake in preheated oven at 180C for 40 minutes. Turn the finished cake on a wire rack. Once cool completely dusted with powdered sugar.