12 heads of garlic will equal about 1 cup of garlic powder. 6 heads of garlic will equal about 1/2 cup of garlic powder. 3 heads of garlic will equal about 1/4 cup.
Garlic powder takes between 3-7 hours to dry in the oven depending on your oven temperature and properties of the garlic (how thin it’s cut, how dry/wet it is to begin with).
3. Prepare a large baking sheet by lining it with parchment paper. Arrange the sliced garlic on the parchment paper, ensuring that they are not overlapping.