Step 1Heat the oil in a 4-quart pot over medium-high heat. When hot, add the onion. Cook, stirring often, until softened, about 5 minutes. Add the cabbage, crushed tomatoes, beef and chicken broths, sugar, paprika, red pepper flakes, allspice, salt, pepper to taste and the water. Stir well. Bring to a boil, then reduce the heat and simmer, covered, 20 minutes.
Step 2Add the sausage and tomato soup. Simmer 10 minutes longer. (This can be made 2 days ahead and refrigerated or frozen up to 1 month. To serve, gently reheat until hot. Add more water if the soup is too thick.)
Step 3Stir in 3 tablespoons of lemon juice. Taste; adjust the lemon juice and seasoning. Serve hot, garnished with parsley or chives, if using.