Peel and mash the banana. Peel and grate the apple. Pour both ingredients into a cereal bowl. Add the fruit muesli (chocolate and other muesli are also good) and mix with the fruit. Now just add enough orange juice until the muesli is moist enough - but it shouldn`t swim in the orange juice.
This is the basic recipe, of which you can make many delicious variations. First, you can mix in a finely grated carrot. Or you can mix in a few teaspoons of cocoa powder (e.g. from Kaba) instead of the carrot - together with one or two teaspoons of honey. Chopped almonds and nuts are also always good in muesli.