For the caramel cream, put the cream cheese, crème fraiche, vanilla seeds and 50ml/2fl oz of the double cream in a bowl and whisk until well combined.
Put the dulce de leche and salt into a small bowl and mix. Lightly fold into the cream mixture until just marbled through. Set aside.
Heat the sugar in a frying pan until golden-brown and liquid. Add the banana and coat in the caramel.
Remove the banana, whisk the butter and the rest of the cream into the caramel in the pan, then put the banana back in and coat once more.
To serve, crumble the biscuit onto a serving plate, place the caramel-coated banana on top, drizzle with the caramel sauce from the pan you cooked the banana in. Finish with a scoop of caramel cream. Finally, sprinkle the grated chocolate over the top.