My Mom's version, which we think is delicious, is this:
Melt margarine or butter in double boiler--about 3 Tblsp. If you want Celery/Onion, or both, chop fine and add to margarine. Let cook until tender.Add about 3-4 Tablsp. flour and stir well
Add tomatoes and stir until well blended. Heat in the double boiler until hot.
Add 1 t. baking soda-releases the gas in the tomatoes. Stir well until no more bubbles from the baking soda are showing.
Add 2-3 cups milk, stir well and get hot. Stir occasionally.
If soup is too thin, dissolve 1-2 T. flour in milk until a light creamy consistency and add to the soup. Stir well.
Add pepper, but no salt--can cause curdling.
Enjoy!!
Mariah