Ok so this was a "look in the fridge and seee what needs using" recipe, s;ightly based on the Red onion and tomato soup recipe from one of the New Covent Garden Soup Company recipe books.
1/2 red onion
one small jar of tomato frito (could also use chopped tomatoes)
1-2 tablespoon tomato puree
1-2 teaspoon balsalmic vinegar
1-2 teaspoon sugar (brown is best)
2 red (bell) peppers
2 cloves of garlic
Put the two peppers whole, under the grill. Keep the grill on high, and turn the peppers occasionally, until the skin is blackened and blistered, and the flesh is very soft. Remove from heat and put in a plastic bag, and seal the bag. Leave to cool for 10 minutes.
In a small pan, pour in a tablespoon of oil, heat. Add chopped onion and crushed garlic (mine was smashed over the top by the chopping board). Fry gently for a few minutes. Add the tomato frito, pure, vinegar and sugar to taste. Stir until smooth and the sugar is dissolved.
When cool enough to handle, remove the peppers from the bag. The skin should come away easily when you pull. Deseed the peppers, chop the flesh and flesh (including the juice rolling out!) into the saucepan. Continue to stir and leave on the heat for 5 minutes
Remove from heat, cool slightly, and puree the soup. Serve with salt and pepper to taste.
This made two generous portions. The soup was gorgeous, took about 25 minutes to cook, and almost tasted creamy, yet was incredibly low fat, and had around 7 portions of veg in the pan (based on NHS guidelines, one portion equalling half a pepper  one onion [1/2] half a tin of tomatoes  one heaped tablespoon of tomato puree