Fat-Free Roasted Garllic

I was watching the "5 Ingredient Fix" on Food Network yesterday, and the host was making Lemon Chicken Soup:
http://www.foodnetwork.com/recipes/claire-robinson/lemon-chicken-soup-recipe/index.html

The soup sounds really good, and I'll have to try it some day, but the part that intrigued me was that she roasted garlic, using no oil, to add to the soup. I tried it last night and spread it on some french bread, and it was really, really good! Below are the directions for roasting the garlic.

Preheat the oven to 400 degrees F.

Put the garlic halves, cut side down, on a sheet of aluminum foil on a rimmed baking sheet. Add 2 tablespoons chicken stock and wrap the foil around the garlic, keeping the cut sides flat on the sheet tray. Roast until the garlic is very soft, about 30 minutes. Remove the garlic from the oven and let stand until cool enough to handle.