Ardeshir was the master librarian for Valid Logic in 1986. He was deeply interested in food especially his own Persian food. He taught me to appreciate the regional foods and how to shop for Persian ingredients. These Persian onions are great as a condiment for cooking such as rice, vegetable dishes, stuffing’s, dressings, sauces, soups and onion dip. The onions sweeten like raisins in the sun by this slow drying process. It is best to do a whole lot of onions at a time as the oven is on for a long time and the volumetric yield is low. Onions reduce in volume 30:1 or more. Six whole chopped onions make a cup and a half of dry product.
Chop uniformly 6-10 large yellow onions. Set your oven on its lowest temperature. (170o F) Prop the oven door slightly open with wooden spoon. Dry onions on Teflon sheet pans on multiple racks. Turn onions over several times to expose wet onion with a spatula. Onions are done when all are a deep camel brown. They will begin to turn pink before this stage. (Five to six hours.) Store up to a year in an air tight jar.
These onions may be ground, once dried, into onion powder. Use the onion powder to make onion pastry dough or simply as a condiment. I use an old coffee mill for grinding.