Cut the red peppers into quarters, remove seeds and membrane.
Grill until the skin blackens and blisters.
Place on a cutting board, cover with a tea towel, and allow to cool before removing and discarding the skin.
Mark a small cross on the top of each tomato.
Place them in a bowl, cover with boiling water for about 2 minutes.
Drain and cool.
Skin, halve, and remove the seeds.
In a large heavy pan, heat the vegetable oil over low heat.
Add marjoram, mixed herbs, crushed garlic, and curry paste.
Stir for 1 minute until aromatic, then add the sliced red onion and leek.
Cook for a further 3 minutes.
Add the cabbage, tomatoes, grilled peppers, and 1.
2 liters (2pt) water.
Bring to a boil, reduce the heat, and simmer for 20 minutes.
Allow the soup to cool slightly, then purée in a blender or food processor for 30 seconds or until smooth.
Return to the pan and reheat gently.
Stir in the sweet chili sauce and season with salt and pepper.