Slice the top 1/2 inch off the heads of garlic. Trim the root end just enough to clean, leaving cloves attached. Use the smallest ovenproof dish or pan that will hold the heads comfortably in a single layer without touching. Stick the garlic head and container with 1 tsp oil. Add the broth or water. Roast on the center rack of a 500 degree oven for 25 to 30 minutes.