Heat the oil in a large
saucepan, add the onion and sprinkle with the caster
sugar. Cook gently for 5 minutes.
Add the chopped carrot and
potato, cover the pan and cook over a low heat for a
further 10 minutes, without browning the vegetables.
Stir in the garlic, tomatoes,
tomato puree, herbs and stock, and season to taste
with salt and pepper. Cover the pan with a
tight-fitting lid and cook gently for about 25-30
minutes, or until the vegetables are tender.
Remove the pan from the heat
and press the soup through a sieve or food mill to
extract all the skins and pips. Season again with
salt and pepper to taste.
Reheat the soup gently, then
ladle into four warmed soup bowls. Finely chop the
sun-dried tomatoes and mix with a little oil from
the jar. Add a spoonful to each serving, then
scatter the shredded basil over the top.