Place pork belly on a tray. Rub 2 tsp salt flakes into the skin and bring to room temperature.
Preheat oven to 150°C. Wipe off any excess moisture with paper towel and drizzle pork with 1 tbs oil. Roast for 45 minutes or until meat is cooked through and tender. Increase oven to 200°C and cook for a further 30 minutes or until skin is golden and crisp.
Boil eggs to a medium to hard boil depending how you like them, add to cold water and allow to cool, peel and set aside.
Add pak choi to a pan with a little oil and fry on a medium heat for 5 minutes, until lightly crispy and set aside.
Meanwhile, combine sugar, 50g miso and mirin in a bowl. Baste the pork with paste. Roast for a further 15 minutes or until lightly caramelised. Remove from oven and set aside to rest for 15 minutes.
To make miso broth base, heat remaining 1 tbs oil in a large saucepan over medium/low heat. Add garlic, ginger and shallot, and cook, stirring, for 2-3 minutes or until softened and fragrant. Add remaining 50g miso and stock, increase heat to medium-high and bring to the boil.
In a small bowl add the sliced spring onion and pour over boiling water and allow to sit until ready.
Simmer for 3-4 minutes to infuse. Spoon stock and noodles into bowls. Add the pork belly slices and serve on noodles with a halved egg, pak choi and spring onion.