Saute onions in 1/4 pound butter until translucent, add cabbage and saute until soft but not brown. Put carrots in pan and saute until soft. Make sure none of the vegetables get brown.
In a large stock pot, put in 1/2 of a pound of butter to melt. Once melted, put in canned tomatoes and saute until most of the tomato liquid is gone. Add in the sauteed vegetable mixture and vegetable stock. Add the bay leaves. Add in the raw beet. Bring to a boil, then reduce heat and simmer gently until the beet is soft.
Once the beet is soft, remove from pot and let cool to touch. In the meantime, peel and dice potatoes. Put half of the potatoes in the soup and cook until soft. Bring the other half of the potatoes to a boil in another pot and cook until quite soft. Drain and mash with remaining butter, 1 cup cream, salt and pepper. Add to soup pot
Peel the beet and coarsely shred, add to soup pot along with the fresh spinach, green bell peppers and remaining cream. Bring to a simmer for 1/2 hour. Add the fresh dill and adjust seasoning to taste. Serve in big bowls with a dollop of sour cream on top for garnish.