Brown hamburger and onion. Drain, add cabbage. Steam until tender. Add soup and 1/2 can milk. Grease a 9x13 pan. Press one package of crescent rolls in the bottom of the pan. Put the hamburger mixture on top. Flatten the other package of rolls out and put on top. Sprinkle cheese on top of hamburger before the dough, if desired. Bake at 350ยบ for 30 minutes.