- If it's some kind of Italian, tomato based soup, the rind of parmesan cheese goes a long way. Also, a Tbs +/- of tomato paste gives its that ' its been cooking all day' flavor to its.
- In Asian soups, I like to sprinkle some MSG, slice shiitake a few drops of sesame oil, white pepper
- Bean soups, split pea ... Ill add a few drops of liquid smoke ( a little goes a long way)
- A bay leaf also adds a lot of underlying flavor ( so does thyme) but both soup specific
- 'Cream of ' soups, I like white pepper. Adds a little heat along with a unique flavor.