Preheat the oven to 190°C.
Cut the onion into wedges, the red pepper into chunks, the cauliflower into 1 cm thick steaks.
Arrange them in a baking tray, add the oregano, chilli (as whole), oil and seasoning.
Roast in the oven for 25 minutes or until the veggies are tender.
Take the tray out of the oven, remove the skin of the pepper, chilli and onion.
Put all veggies in a saucepan, including the jus. Add the tinned tomatoes, garlic and stock.
Bring to the boil and cook for 5 minutes.
Using a stick blender, pulse the soup until you get a coarse texture - this soups should not be too smooth. Add more stock, if it's too thick.
Add the drained lentils and reheat the soup, then add the coriander leaves.