Grilled scallops with sweet chilli sauce and crème fraîche

12 large diver-caught scallops, trimmed

sesame oil

salt

pepper

watercress leaves

½ cup crème fraîche

For the sweet chilli sauce:

10 garlic cloves, peeled

4 large red chillies, stems removed

3 thumbs of fresh ginger, peeled and roughly chopped

1 thumb of galangal, peeled and roughly chopped

8 lime leaves

3 lemon-grass stems, remove the two outside leaves, discard the top third of the stem and finely slice the remainder

1 cup fresh coriander leaves 

1½ cups unrefined golden caster sugar

100ml cider vinegar

50ml Asian fish sauce

50ml tamari