Step 1

Peel and slice the onions. You can use a mandoline to get really even, thin slices. The thinner the slices, the quicker they’ll dry. Aim for 1/8 inch at the thickest.

Step 2

Lay the fresh chopped onion over the dehydrator trays in a single layer, taking care not to make them overlap too much, and then dehydrate at 66ºC/150ºF for 6-8 hours (if high humidity, around 80%) or 4-6 hours (if low humidity).They are ready when they snap when trying to bend. If they're at all pliable, they need more time.

Step 3

Spread the onion pieces over parchment-lined baking sheets, making sure the pieces don't overlap too much, and then place in the oven at its lowest temperature. It's best if it's between 130-150ºF (54-66ºC).If your oven doesn't go as low as that, then choose the lowest temperature and prop open the door with the handle of a wooden spoon or something similar, to allow for better airflow and for the steam to escape as the onion dehydrates.Check on the onion hourly, optionally flipping it over a couple of times, to dry it faster. Remove from the oven when it snaps rather than bends.

Step 4

Place the onion slices on a large kitchen towel/cloth or paper-lined baking tray and leave them in a well-ventilated area ( air circulation is needed!), near a window (if possible).This option is best for warmer, non-humid climates with lots of sunshine. Colder and more humid areas will affect the drying time.Flip the onion pieces a few times to speed up the process. This method can take a few days based on the onion's thickness, weather, and humidity. They're ready when the onions are completely dry.

Step 5

Store the dehydrated onion flakes in airtight glass jars, and keep them in a cool, dry, and dark location - like a kitchen cupboard.

Step 6

The flakes will keep well indefinitely in an airtight jar in your kitchen, as long as it remains 100% moisture free! You can also place some uncooked rice or beans into the container, which will absorb excess moisture and stop them from clumping. They’re best when used within the first year, though, as the flavor will deteriorate after that, I've found.