Cut the plums into quarters and take out the stones.
Heat the pan with the butter and then add in the plums and toss around for a couple of minutes until they are glazed. Scatter in the sugar and cook for 3-4 minutes. Just before serving add in a splash of Grand Manier and allow that to flame up. Be very careful not to get burned.
Place the orange juice, sugar and vanilla pod into a small saucepan and boil continuously for 5-6 minutes until it has reduced to a thick syrup.
In a separate bowl mix the crème fraiche with the vanilla seeds and store in the fridge until required.
Heat a large pan with a little butter and place the Madeira cake into the pan and cook on both sides until golden brown. If you are doing a lot of these or if you would prefer not to stand over a pan you could place the cake onto a flat baking tray with the butter and bake until golden brown instead.
Serve the cake in a large bowl with the flambéed plums on top. Drizzle with the orange syrup and top with a quenelle of crème fraiche and a sprig of fresh mint.