Whisk the oil, mustard and Soya sauce in a bowl.
Add the tuna and coat evenly.
Roll in cracked black pepper.
Heat a sauté pan and sear for about 30 secs on each side.
Remove and Slice for Service.
Pour the stock into a pot and bring to the boil.
Meanwhile heat the oil in a large frying pan or wok.
Add a third of the noodles and fry until they puff up. Remove and drain.
Add the shallots, ginger and garlic and stir fry for a minute.
Add the curry paste.
Add the stock and the noodles and cook for a couple of minutes until the noodles are cooked.
Finish with the two sauces and chopped coriander.
Wok Fried Pak Choi:
Slice the stems on a diagonal bias and halve the leaves.
Heat the sesame oil and fry the garlic and chilli, add the stems and cook for a minute.
Add the leaves and gently wilt.
Place the Pak Choi in the middle of the bowl.
Ladle the soup around the pak choi.
Place the sliced tuna on top of the pak choi and garnish with the fried noodles.