Separate the egg yolks and place them in a large mixing bowl. Add sugar and vanilla extract to the yolks and whisk until smooth and well combined.

Mash the ripe bananas in a separate bowl, then stir them into the egg mixture. Pour in the milk and whisk until everything is fully blended.

In a small bowl, mix the cornstarch with 20 ml of milk until completely dissolved. Stir the cornstarch mixture into the banana custard mixture and whisk to combine.

Pour the mixture into a saucepan and cook over low heat, stirring continuously for about 10 minutes, until it thickens to a smooth, custard-like consistency. Remove from the heat, divide between four dessert glasses, and let cool at room temperature.

Melt the butter in a small pan over medium heat. Add the sugar and stir until it dissolves and turns a light golden caramel.

Slice the banana and add it to the pan, stirring gently to coat each piece. Let the caramelized banana topping cool to room temperature.

Spoon the cooled bananas foster topping over the pudding. Chill for at least 3 hours or until fully set before serving.