1. Peel and finely chop your onions.
2. Then, spread the onion pieces out on a tray and heat in a 150 degree oven or in a food dehydrator until dry.
Tip: The onions are dry when you can easily crumble the chopped pieces in your hand.
3. Allow the onions to cool. Then, grind with a coffee grinder, spice mill, food processor or mortar and pestle until you reach your desired consistency.
4. Store your finished onion powder in an air-tight container in a cool, dry spot or freeze.