30 ml olive oil
900g Tomatoes, halved
2 garlic cloves
1 small potato, peeled and sliced
300 ml water
5 ml sugar

Lightly oil a roasting tin. Arrange the tomatoes, cut side uppermost in the roasting tin. Add the garlic cloves. Season and drizzle over the remaining oil. Roast in the oven at 190°C (375°F/Gas mark 5) for 30 minutes.
Boil the potato in 300ml water until tender. Do not drain the water.
Skin the tomatoes and the garlic and put the tomato pulp and garlic into a food processor or blender with the cooked potato and potato stock and blend until smooth.
Transfer to a saucepan. Add a little extra vegetable stock or water if the soup is too thick. Stir in the sugar.