Cook cabbage in boiling water just until leaves fall off of head. Set aside 12 large leaves for rolls, store the rest in refrigerator for another recipe. Cut out thick vein in center of each leaf, making a v-shaped cut. Set aside.
In large bowl, combine tomato sauch, rice, cracker crumbs, egg, and soup mix. Crumble meat over top and mix well.
Place about 1/3 cup of meat mixture onto each leaf. Overlap cut ends of leaf. Fold in sides, beginning from the cut end. Roll completely, and secure with toothpicks if desired.
Place rolls in slow cooker. Pour juice over top. Cover and cook on low setting 6-7 hours or until rolls reach 160 degrees on inside.
Sprinkle with salt if desired, right before serving.