Can you convert fresh chopped onion to onion powder?

Yes, you can convert fresh chopped onion to onion powder by drying the onions first. Slice the fresh onions thinly and then dehydrate them using a food dehydrator or an oven set at a low temperature until they are completely dry and brittle. Once dried, grind the pieces into a fine powder using a spice grinder or blender. Store the onion powder in an airtight container for future use.