In a medium bowl, combine cornflour, soft dark brown sugar, crushed garlic cloves, dark soy sauce, oyster sauce, and chicken stock. Whisk together until smooth and set aside.

Place the dry noodles in a large bowl and cover with boiling water. Let them soak for 4-5 minutes until tender yet firm, then drain.

In a large frying pan or wok, heat the sunflower oil over medium-high heat. Add the sliced chicken breast seasoned with Chinese 5 spice. Stir-fry for 6-7 minutes until lightly browned.

Add the stir-fry vegetable mix and stir-fry for 4-5 minutes, keeping the vegetables vibrant and tender-crisp.

After draining the noodles, add them to the pan with the chicken and vegetables. Pour the sauce mixture over and stir well. Cook for 3-4 minutes until the sauce thickens.

Gently mix everything together and garnish with chopped spring onions before serving for added freshness and color.