Oddly enough the hot stinky cheap onions have more cancer fighting vitamins than those really sweet ones! Here is a good way to cook them to make them sweet and delicious! In fact, when cooked they are always sweeter. The sweet varieties are best eaten raw because when cooked they are less sweet.
Peel and core (with your apple corer) a large onion - don't poke the corer all the way through.
Place the onion on a sheet of foil. Put a bullion cube in the core, top with a 1/2 teaspoon of a butter substitute, sprinkle with thyme and pepper. Pour a teaspoon of dry sherry over all and grill for 45 minutes or until completely soft. Open and enjoy - it will taste like sweet French Onion Soup! Make one for each person because you won't want to share!