Make your own onion powder by baking finely chopped onions in the oven until they're crisp, then grinding them into a smooth powder. You will fall in love with how much better better this tastes compared to store bought spices!
Preheat oven to 170 degrees F. In case yours doesn’t go that low, I find that temperatures from 150-190 degrees F work well.
Peel the onions and chop them up finely. 5 medium-sized onions will make about 1/2 cup onion powder, 10 onions will make about 1 cup of onion powder.
Line a large baking sheet with parchment paper, and then place diced onions on top, trying to prevent them from overlapping.
Place onions in the oven and bake until they are crisp and can easily snap in half. If they are soft and bend (don’t snap), then they aren’t ready yet. In general, onions take a few hours, anywhere from 3-7 hours depending on oven temperature, onion type and how big the onion pieces are. Check them at every hour, giving them a stir until they are done.
Remove onions from oven and allow to cool. Place the diced onion in a coffee or spice grinder. You might need to do this in batches depending on how many onions you have.
Grind until you have a smooth powder. After I grind them, I like to sift to make sure to remove any larger pieces that didn’t grind up.
Store onion powder in an airtight spice jar in a dark, cool cabinet. Onion powder will stay fresh for 1 year if stored properly. Use as needed and enjoy your homemade onion powder! One onion (or 1 cup of onions) equals one tablespoon of onion powder.