Firstly, make your custard.
Heat the milk in a saucepan until it is hot but not boiling.
In a mixing bowl, whisk together the egg yolks, cornflour, sweetener or sugar and vanilla essence.
When the milk is hot, whisk it into the egg mixture a little at a time. Be careful to add it slowly. If you pour it in too fast you will scramble the eggs!
Pour the custard mix back into the pan, and place on a low heat. Keep whisking until it thickens and bubbles begin to break the surface. Don't be tempted to rush this. Increasing the heat will curdle the sauce and you will end up with a scrambled eggy mess! Allow the bubbles to break the surface for 30 seconds while you continue to whisk, then take off the heat.
Scrape out of the pan into a bowl cover with cling film and allow to cool. When cold enough, pop it into the fridge for half an hour to chill.
When cold, finely chop or lightly mash the bananas reserving a few slices for decoration and stir them into the cold custard.
Whip the cream until thick and fold into the banana custard mix.
Spoon into 4 individual glass dishes, top with the crumbled Flake and reserved banana slices. Enjoy!