Chop the tomatoes into cubes. Heat oil and 1tsp butter in a pan. Now add ginger and garlic and saute. Then add the onions and fry for a few seconds. Now add tomatoes and saute for 3-4 minutes. Now transfer the tomatoes into a blender and blend to a fine paste along with a little water. Strain the mixture to discard the peels. Now put the mix in the pan adding required amount of water and cook. Add salt, sugar, tomato sauce when it starts boiling. Check the taste of sweet and sourness and adjust.

In a separate bowl mix corn flour with a little water and add to the pan. Keep on stirring so that corn flour dissolves well. If you like can add a few drops of food color. After adding cornflour do not overcook because it may result to too much thickening of the soup. You can adjust the consistency by adding water. When the soup is of right consistency give a finishing touch with spring onion, pepper powder and 1tsp of butter. Serve by garnishing with crouton and spring onion or mint leaves.