Preheat the oven to 200C/400F/Gas 6.
Place all the pastry ingredients together in a food processor and blend until a dough forms. Wrap the dough in cling film and transfer to the fridge to chill for 10 minutes.
For the fruit, melt butter in a small ovenproof frying pan over a medium heat. Add the sugar and stir until dissolved.
Add the galangal or ginger to the frying pan and cook for two minutes.
Add the nectarines to the frying pan, with the cut side facing down. Cook for five fminutes until they become soft and brown underneath.
Roll out the pastry on a lightly floured surface. Cut a disc to match the diameter of the frying pan and use to cover the nectarines. Pinch the edges to seal and transfer the frying pan to the oven. Bake for 12 minutes, or until golden brown and cooked through.
To serve, turn upside down over a serving plate and tip out. Dust with icing sugar and serve with the whipped cream.