Preheat oven to 400 degrees. Cut top off of entire head of garlic to expose cloves.
Place garlic head in one hole of muffin tin and drizzle with olive oil.
Place muffin tin in oven and roast until garlic is hot and seems to slightly bubble (about 25 minutes).
Turn oven to a low broil. Place bread slices on cookie sheets and broil until toasted, about 3-4 minutes on each side.
Place bread on table alongside roasted garlic (still in the head), halved tomatoes, olive oil, and a small bowl of salt. Have each guest assemble their toast with whichever ingredients they choose. Use a knife to remove roasted garlic from the head, and rub the entire half of the tomato on the bread.