1. Preheat the oven to 180C/160C fan/gas 3. Cook the pork belly pieces in a pan of boiling, salted water for 2-3 mins, then drain and plunge into a bowl of cold water.
2. Meanwhile, combine the milk, stock, soy and honey in a pan. Add the ginger, salad onion, fennel, cumin and coriander seeds. Heat until bubbling.
3. Put the pork belly pieces in a deep ovenproof dish and pour over the broth. Braise in the oven for 90 mins or until tender.
4. Preheat the grill to high. Drain the broth through a sieve into a clean pan; reserve. Transfer the pork to a lined baking tray and pat dry. Brush with the olive oil and grill for 2 mins on each side or until crispy.
5. Meanwhile, cook the noodles to pack instructions, adding the spinach for the final minute to wilt; drain and divide between bowls. Spoon over a little of the broth, then top with the pork, radish and a drizzle of chilli oil, if using. Leftovers will keep chilled in an airtight container for 2-3 days.