For the basil soup, chop the onion and sauté in hot oil until translucent. Peel the potatoes, cut into cubes, add to the onion and sauté briefly.
Add the vegetable soup and simmer for 5 minutes. Wash basil and set aside some beautiful leaves for garnish.
Roughly chop the remaining basil, add to the soup and simmer for another 5 minutes. Turn off the heat. Add silken tofu and puree everything with a blender.
Season the basil soup with lemon juice, salt and pepper.