In dutch oven or large saucepan, heat nine cups water to boiling. Place cabbage leaves in boiling water. Remove from heat. Cover and let stand until leaves are softened, about ten minutes.
Mix meat, rice, onion, mushrooms (with liquid), seasonings and 1/2 cup of the tomato sauce. Remove cabbage leaves from water, drain. Place about 1/2 cup meat mixture at stem end of each leaf. Roll leaf around meat mixture, tucking in sides.
Place rolls seam side down in pot. Mix remaining tomato sauce and sugar. Pour over rolls and heat to boiling. Reduce heat, cover and simmer until meat is cooked, about 45 minutes.
Cajun Country -- New Iberia, Louisiana