Cut 24" x 16" piece of heavy duty aluminum foil. Chop medium head of cabbage. Butter the whole piece of foil. Place cabbage on foil. Season with garlic salt, pepper and several pats of butter. Bring sides together and fold, then bring ends together.
Could also add diced onion, sliced potatoes and kielbasa. Place on coals of grill for 1 hour. Turn at least once.