If you have a real wood fire or large pile of coals you're cooking over, my favorite is to bury just below the surface of the fire a couple of large onions without peeling ANY skin off before burying (actually cover them up with coals). Leave in till outer part is beginning to turn a definite "burned black" all over (just pull back some coals to see). Make sure heat is even all around the onion while buried. When done, pull out with metal tongs, let cool, cut in half & peel off the outer burned layers. Cooked all the way through is desired. Most wonderful juicy onion I've ever had.