To make the paste: Remove the loose, papery outer skin from the heads of garlic. Using a sharp knife, cut about 1/2 inch off the top to expose the cloves. Place each garlic head on a large square of heavy-duty aluminum foil and drizzle 1 tablespoon of olive oil over the top of the cloves. Fold up the foil sides and seal to make a packet, leaving a little room for the expansion of steam. Grill over Indirect Medium heat until the cloves are soft, 45 minutes to 1 hour. When cool enough to handle, squeeze out the garlic cloves into a medium bowl. Add the remaining paste ingredients, including the remaining 1 tablespoon of oil. Using the back of a fork, or a mortar and pestle, thoroughly combine the ingredients to create a paste.