Preheat oven to 375 degrees F. Remove the papery outer covering of whole garlic head, but do not separate the cloves or peel them. Place as many whole heads of garlic on a large square of heavy-duty aluminum foil as there are people to be served. Fold up foil so that the cloves are completely wrapped. Bake in the preheated oven for 1 hour 15 minutes. Serve each diner a head of garlic and some bread and butter. Separate cloves. Hold a clove over a piece of buttered bread and squeeze. The garlic puree will pop out, like toothpaste from a tube. Spread and eat.
GARLIC PUREE: To make a batch of Garlic Puree for later use, let roasted heads of garlic cool, unwrapped for at least 5 minutes. Gently separate the cloves and squeeze each one over a fine meshed sieve, so that the softened garlic pops into the sieve. With wooden spatula or wooden spoon, rub garlic through the sieve into a small container or bowl. Cover tightly with plastic wrap and refrigerate the puree if needed.
QUICK PUREE: If you are in a hurry, you may skip the refinement of the sieve. Simply squeeze the cloves, one by one, over a bowl. When they have all been squeezed, use a rubber spatula to push the puree into a neat mound cover tightly with plastic wrap, and refrigerate until needed. It will keep for months. To keep indefinitely, cover with a film of olive oil.