- Step 1
Position a rack in the centre of the oven and preheat to 190C. Place the bananas on a baking tray lined with foil and roast for 30 mins or until the banana peels are completely blackened and the flesh is soft. Discard the peels. Use a pastry brush to brush 4 round 9cm-wide, 6.5cm-deep ramekins with the butter.
- Step 2
In a blender, puree the banana flesh, milk and cream until smooth. Transfer the banana mixture to a medium heavy saucepan. Scrape the seeds from the vanilla bean into the banana mixture and bring to a simmer over medium heat.
- Step 3
Meanwhile, in a medium bowl, whisk 40g of the caster sugar and the yolks for 1 min or until light and fluffy.
- Step 4
Whisk the flour into the egg mixture, then gradually whisk in the hot banana mixture. Return to the saucepan and bring to the boil over medium-high heat. Boil for 2 mins or until the custard has thickened. Transfer the banana custard to a medium bowl. Press a sheet of plastic wrap directly on the surface of the custard and cool to room temperature.
- Step 5
In the bowl of an electric stand mixer fitted with the whisk attachment, whisk the egg whites and cream of tartar on medium-low speed for 3 mins, or until the egg whites begin to froth. Increase the speed to medium and whisk for a further 2 mins, or until the egg white liquid has mostly dissipated. Slowly add the remaining 60g caster sugar. Increase the speed to medium high and whisk for 2 mins or until soft peaks form.
- Step 6
Place a sturdy baking tray in the preheated oven. Whisk one-third of the whipped egg whites into the banana custard. Fold in one-third of the egg whites then fold in the remaining egg whites. Immediately divide the mixture evenly among the ramekins.
- Step 7
Place the ramekins on the preheated baking tray and bake for 15 mins or until the soufflés have risen and are still a bit liquid in the centre. Dust with icing sugar and serve immediately with ice-cream.
You can make the banana custard to the end of step 3 up to 1 day ahead, then cover and refrigerate. To finish the souffles, bring the banana custard to room temperature then continue from step 4.