Preheat the oven to 200°C.
Wash the tomatoes and arrange them in a roasting tin (leave them on the vine).
Drizzle 3 tbsp oil over them and bake for 20-25 minutes until soft .
Take them out of the oven and, when cooled a little, mash with a fork and discard the vines.
Transfer the tomatoes and all the juices into a liquidiser, add the sugar & basil and blend until smooth.
If you prefer a silky smooth soup , pass it through a sieve.
Season to taste and warm it up if necessary.
Serve with a few basil or oregano leaves scattered on top.