In a large pot over high heat, combine the water, salt, carrots, green bell pepper, celery, beet, 1/2 cup tomatoes and the potatoes. Bring to a boil.
Meanwhile, in a separate skillet over medium heat, melt the butter and saute the onions in the butter for 5 minutes. add the 1 1/2 cups tomatoes, reduce heat to medium low and let simmer for 15 minutes. Take out 1/2 cup of this sauce and reserve for later. Add half the cabbage to the sauce and continue to simmer.
Discard beet from boiling mixture. Remove potatoes from pot. Mash and add 1 tablespoon butter and the cream. Mix well and set aside.
Add the 1/2 cup of reserved onion-tomato sauce to stock. Also add the diced potatoes. When diced potatoes are tender, add remainder of cabbage (1 1/2 cups). Bring to the boiling point, but do not boil. Put tomato sauce mixture from frying pan into pot. Add mashed potato mixture. Add green pepper and a few shakes of black pepper.
To Freeze: Freeze in freezer safe container.
To Reheat: Reheat in a covered pot until hot.