Blanch the broccoli, cauliflower florets and carrot in boiling water for 1–1½ minutes. Drain and place in a bowl of cold water to ensure a crispy texture. Drain again and place in a bowl with the other vegetables.
Heat 7 cm (3 inches) oil in a wok on medium heat. The oil is ready when a piece of noodle sizzle immediately when dropped in. Deep-fry each nest of noodles for 5–6 minutes or until crispy. Drain on kitchen paper and keep warm.
Pour the oil out of the wok, leaving behind about 1½ tablespoonfuls and stir-fry the garlic on a medium heat for 1–2 minutes or until lightly browned. Add the mixed vegetables, bean sprouts and ginger and stir-fry for another 3–4 minutes. Add the stock, light soy sauce and 3½ tablespoons oyster sauce and toss together. Add the spring onions. Taste and adjust the seasoning, adding the rest of the oyster sauce if necessary.
Arrange the noodles on serving plates and spoon over the mixed vegetables. Garnish with coriander leaves and serve.