Preheat the oven to 400°F. Cut twelve 4-inch squares of parchment paper and twelve 4-inch squares of aluminum foil. Lay a parchment square on top of each foil square.
2
Slice 1 / 8 inch off the top of each head of garlic to expose the cloves and place the heads in a baking dish. Pour the oil over the tops of the heads of garlic, letting the oil sink down into the cloves, then sprinkle the tops with the salt.
3
Put each head of garlic on a square of parchment placed on a square of foil and wrap the head tightly. Put the wrapped garlic in a 9-inch square baking dish.
4
Roast the garlic for 20 minutes, or until soft. Even after it is soft, you can continue roasting until it is deeply golden for a sweeter, more caramelized flavor—check it every 5 minutes. The exact roasting time will depend on the size of your heads of garlic, the age of the garlic, and the variety.
5
Allow to cool, then squeeze the garlic cloves from the skin as needed. Store unused roasted garlic in the skin in the freezer for up to 3 months