This recipe is our tribute to Nadine Ingram's insanely good panna cotta lamingtons at her Sydney store, Flour and Stone. You could say we're obsessed. Ingram's original recipe takes a panna cotta-soaked vanilla sponge cake and transforms it into the lushest of lamingtons. For our version, we've opted for chocolate sponge cake and chocolate panna cotta. This recipe makes a mega-cake, but if you're feeding fewer people, make a single cake and split it in half horizontally to fill it.