Prep: Preheat oven to 250°F (121°C). Either peel the garlic cloves completely, or separate the cloves from the head, leaving the paper on.
Assemble: Add garlic and oil to an oven-safe pan (like a cast iron or casserole dish). If garlic is not submerged completely, add a bit more oil. If desired, add a few hearty herbs to the pan.
Cook: Cook for 2 hours, or until garlic cloves are golden brown and soft. Remove from oven and let cool.