Heat oil in soup pot. Add onion and garlic and saute over med-low until golden.
Add water and bullion cubes, mushrooms, cabbage, and seasonings. Bring to a rapid simmer, then lower the heat. Cover and simmer gently for 15 minutes.
Meanwhile, set aside 1 cup of the chickpeas and place the remainder in a food processor or blender with the tahini. Add a little water as needed to thin the consistency. Process until smoothly pureed. Stir the puree back into the soup pot.
Stir in the reserved chickpeas, bring to a simmer, then cover and simmer very gently for 10 minutes.
Stir in parsley, scallions, dill and lemon juice. Add water as needed for medium-thick consistency.
Season with salt and pepper, then simmer for 5 minutes longer.