Combine beaten egg, custard powder, sugar, milk and cream in medium, heatproof bowl and whisk until mixture is smooth.
Place the bowl over a pan of simmering water. Stir mixture constantly for 5 minutes or until custard thickens slightly and coats the back of a wooden spoon.
Remove bowl from heat and gently stir in the sliced banana. Serve sprinkled with coconut and cinnamon, if desired.
Note: For variety, custard may be flavoured with a few drops of almond or vanilla essence.
