Heat oil in a saucepan. Add garlic, ginger, and green chilies. Sauté for 30 seconds.
Add onions and sauté until translucent.
Add carrots, cabbage, capsicum, beans, and mushrooms. Stir-fry for 3-4 minutes.
Pour soy sauce, vinegar, red chili sauce, black pepper, and salt. Mix well.
Pour vegetable stock/water and bring to a boil. Simmer for 5-7 minutes.
Add cornflour slurry and stir continuously until the soup thickens slightly.
Pour into bowls, top with fried noodles and spring onions.
Serve hot with extra chili sauce if desired.