Simmer tomatoes in a large saucepan for 10 minutes. Remove from heat and add 1/4 cup butter, soda, 1 teaspoon salt, and sugar. Let cool during preparation of next step. Melt the remaining 1/4 cup butter in large kettle. Add flour and 2 teaspoons salt. Add milk; heat and stir to boiling point. Combine the two mixtures and heat slowly. Add salt, if needed, and pepper to taste. Serve as soon as soup is piping hot. This will be a thin soup. If you prefer, the flour could be eliminated entirely, or you could double the flour for a thicker consistency. This soup is not a smooth mixture, but the chunky tomato pieces add interest. Fresh garden tomatoes give it a delicious flavor.
