My grandma’s trick: never throw away onion skins again

2. Place the onion skins on a baking sheet lined with parchment paper.
Dry in the oven at 60–70 °C (convection) for about 2–3 hours, until they are completely dry and rustle-free. Alternatively, dry in a dehydrator.

3. Place the completely dried peels in a blender, food processor or coffee grinder and grind finely until a powder is formed.

4. Fill the finished onion powder into an airtight glass jar or spice container. Store in a cool, dry place.