Preheat oven to 200C/400F/Gas 6.
Place all the pastry ingredients together in a food processor and blend to make a smooth dough. Wrap the dough in cling film and transfer to the fridge to chill for 10 minutes.
For the scallops, in a clean bowl mix the pak choi, chilli, galangal, soy sauce, sesame oil and sesame seeds, then divide the mixture between the two scallop shells and put their lids back on.
Roll out the pastry on a lightly floured surface. Use the pastry to seal the edges of the shells together. Bake on an oven tray for six minutes.
For the pak choi, heat the oil in a frying pan. Add the galangal, chilli and pak choi and stir fry for 2-3 minutes. Sprinkle with soy sauce and sesame seeds.
To serve, remove the pastry from the scallops and arrange on a plate in their shells alongside the stir-fried pak choi