For the soup, peel the ginger and grate it finely. Cut the tomatoes into cubes. Heat some oil in a large saucepan and briefly sauté turmeric, cumin, curry and ginger, add the lentils and sauté briefly. Add the tomatoes and deglaze everything with the vegetable stock. Let the soup simmer over medium heat for about 25-30 minutes until the lentils are soft. Puree everything with the hand blender and season with soy sauce, salt and cayenne pepper and pour the cream on top. Let the soup boil again.
For the garnish, fry the onions in oil until golden brown and season with the cumin. This is best done while the lentils are cooking until they are soft. Pour the soup into bowls and garnish with the onions.
Indian naan bread goes very well with it.
The soup is very filling and makes a good main course with bread as a side dish. If you want to serve the soup as a starter, you should divide the amount into 6-8 servings, otherwise you won`t be able to make the main course.