Although this turkey (or chicken) broth is time-consuming to make, it really does benefit from simmering on the stove for hours. The whole heads of garlic mellow into deep sweetness, giving the broth an authentic Italian flavor.
Cooks' note:
Broth can be made ahead and cooled completely, uncovered, then chilled, covered, 4 days or frozen in an airtight container up to 3 months.