1. In a large Dutch oven or saucepan, saute onions in vegetable oil for 5 to 10 minutes, or until translucent. 2. Add the potatoes, cumin, and fennel; cook for 1 minute. 3. Add the hot water; cover, turn up the heat and bring to a boil. 4. Add the cauliflower and bouillon cubes and return to a boil. 5. Lower the heat and simmer, covered, for 10 minutes or until the vetetables are tender. 6. In a blender, puree and vegetable/broth mixture until smooth. 7. Add lemon juice, salt, and pepper to taste. 8. Reheat the soup, being careful not to scorch it.