Preheat an oven to 190 degrees (170 for fan ovens).
Put all the vegetables in a baking tin, pour the olive oil, sprinkle with salt, pepper and sugar, stir and put in the hot oven to roast for approx. 50 minutes until the vegetables are soft and slightly caramelised.
Liquidise the vegetables in a food processor.
Add the required amount of stock, bring to boil.
The soup can be served with a drop of cream (for a non-vegan version) or/and pasta.