Sift the baking powder, flour, sugar and salt into a small bowl and set aside.
In a mixer, combine egg, butter, vanilla and milk. Slowly add the sifted ingredients that you set aside. Mix until smooth. Pour in a 9 x 13 x 2 greased cake pan OR two greased layer cake pans. Bake at 375 degrees for 20-25 minutes or until inserted toothpick comes out clean.
Use the following recipe for the icing after cooling:
If you make it as a layer cake, you can place sliced bananas between the layers before frosting. If making one 9 x 13 x 2 cake, frost the cake and sprinkle Baker's coconut over the top.