Put the egg yolk in a heat proof bowl and add the sugar. Place the bowl over a saucepan of simmering water without the bowl touching the water and whisk the yolk and sugar until thick and creamy. The colour of the mix will be lighter when ready. Take the bowl off the saucepan and add the vanilla seeds (keep the bean to add to sugar to make vanilla scented sugar for your baking) and the mascarpone in small amounts and mixing gently after each addition. Serve on top of a thick slice of chocolate banana bread and top with a dollop of salted caramel sauce.
*If you want the sauce to be chocolate flavour simply add the Tbsp of cacao powder at the same time as the sugar and whisk to combine.
