In a large saute pan, melt margarine, add onions and cook over medium heat until translucent. Reduce heat to low.
In a large stock pot, add water and bring to a boil. Add carrots, potatoes, pearl barley, and cook for 10 minutes. Add chicken broth, penne, celery (including leaves), chicken soup base, red bell pepper and green bell pepper and bring back to a boil. Reduce heat and cook for 15 minutes.
Add white pepper, cauliflower florets, parsley, thyme and cook for an additional 5 minutes.
In a food processor or blender, puree 3 cups of all-ready cooked soup and return to stock pot.
In a small mixing bowl, mix together flour and 3/4 cup whole milk; blend well. Add flour mixture to the cooked onions and mix well. Gradually add remainder of milk, stirring constantly until soup is heated through.
Add onion mixture to soup and stir. Add soy sauce and bring to a boil. Adjust seasonings to taste and serve soup hot.
