Season the tomatoes with salt and allow them to sit for a couple of minutes before using.
Heat the vegetable oil in a saucepan over high heat. Add the tomatoes and cook, stirring, for 2 minutes or until the tomatoes start to soften. Stir through the garlic. Then add the chicken stock. Bring to a simmer. Then stir the soup to form a vortex in the centre. Pour the egg into the centre of the vortex and stir vigorously to form the lacy egg.
Add the corn flour, soy sauce and pepper. Simmer for another minute to thicken. Add the spring onion and season with salt to taste.
