Preheat oven to 425 degrees.

Use a sharp knife to cut off the tops of each garlic head to expose the tops of the garlic cloves. Use a paring knife, if necessary, to get any cloves around the outside that aren't as tall so that they are exposed as well. Peel away as much of the papery skin around the outside of the garlic head as you can without the cloves starting to fall off. Rubbing the paper away with your fingers works well.

Place each garlic head on a separate square of aluminum foil and drizzle it with olive oil. Wrap the foil around each garlic head and set on a baking sheet or in a pan with the cut top up.

Roast the garlic in the oven for 45 minutes, until they turn a nice caramel color and the cloves are all soft.

Remove from the oven and unwrap the garlic heads. Let them cool for 30 minutes or so, until they are cool enough to handle. Gently squeeze each clove out of the remaining skin into a small bowl. Use immediately or store in a little olive oil in the fridge for 2-3 days.