Peel the outer layer of the onion off and carve a large hole in the middle of the onion. Place the beef bouillon cube in the hole as well as the butter and ice cube. The ice cube is going to allow the onion to become moist. Wrap the onion in a few layers of foil then poke the foil with a fork at the top of the hole to allow the onion to vent. This will grill on medium heat for 30 minutes or until the onion is nice and soft.
Once it is unwrapped it should just fall right apart into pieces. Eat it just as a side dish by itself or garnish the dinner with it.