In a very large stock pot over medium-high heat, saute the onion in olive oil until soft, about 5 minutes.
Add the garlic, cabbage, bok choy, broccoli, broth, and water. Cover and bring to a boil.
Reduce heat to medium-low and simmer for about 15 minutes.
Add the tofu, parsley, salt, cayenne, and lemon juice. Remove from heat and blend using an immersion blender.