Indian Cream of Tomato Soup

1 1/2 LB ripe tomatoes, chopped
1 TB sliced lemon grass
1 TB dried or fresh curry leaves
1 thick slice of fresh ginger
1 1/4 tsp salt
4 TB unsalted butter
2 TB flour
1/2 cup heavy cream
2 cups whole milk
1/2 tsp ground roasted cumin seeds
1/8 tsp ground pepper
1/8 tsp cayenne pepper
2 tsp fresh lemon juice
1 TB chopped fresh coriander

1. Combine the tomatoes, lemon grass, curry leaves, ginger, 1/2 tsp salt, and 1/4 cup water in a large sauce pot and bring to a boil. Cover, lower heat, and gently simmer for 15 minutes. Uncover, turn heat to medium, and simmer a little more aggressively for another 15 minutes. Put the tomatoes through a sieve. You should have about two cups of thick tomato juice. Bring this juice to a simmer and keep over a low flame.

2. Melt the butter in a heavy sauce pan. Add the flour. Sir and cook the flour on low heat for 2-3 minutes. Do not let it brown. Now pour in the hot tomato juice, stirring all the time. Add the cream and the remaining 3/4 tsp salt. Stir to mix and bring to a simmer. Add all the other ingredients except the fresh coriander. Stir to mix. Heat over a medium flame. As soon as the soup is about to come to a boil, turn off the heat. Ladle the soup into bowls and serve garnished with a little chopped fresh coriander.