What I did...
Just boiled winter melon (ash gourd) and carrots with some rolled barley, with curry leaves, coriander/cilantro, kuzhambu powder, turmeric and salt. Home made tomato paste worked its magic and made the soup sweet and sour. for the tomato paste, blanch tomatoes and grind them...Use the excess water for your soup. One tiny clove of crushed garlic was enough to give it a nice pep. Add a few crumbs of feta cheese and Romano cheese and you have a super yummy soup waiting for you.
Roast a pepper papad (/appalam) in a microwave for the "crunch" and you are good to go.A great way to add urad dal/moong dal (depends on the papad) to your daily meal and feel good about avoiding croutons. Ah!
A low fat, guilt free soup which really fills your tummy. :)