I have to admit that I'm not fond of soup when our temperature here in Florida gets obnoxiously hot. But, Sharon, our long time OFL, invented a really simple soup that can be eaten hot or cold. This sounds like one you could add almost anything you wanted to. I'll definitely try this one! Maybe with a little chiffonade of basil at the end of the initial cooking.
Cold Summer Vegetable Soup
1 can chicken broth
2 stalks celery
1 red pepper
Cut vegetables into bite-size pieces, put into broth, bring to the boil and cook for 2-3 minutes until vegetables are still crisp (other vegetables can be added, too).
Turn off the flame and chill thoroughly. Serve when quite cold for a refreshing accompaniment to a summer lunch.