Oven drying leeks and using them to make homemade leek powder is definitely a great way to use up leftovers and a great way to dip your toes into dehydrating food.
Wash and chop 1 large leek — sometimes I even just do the green tops because I use the rest of the leek for cooking. This is also a really great way to put those tops to use.
Place the chopped leek on a paper towel and pat dry. Let sit overnight so that it really dries out. (You can skip this step, it will just take a bit longer in the oven to get all the moisture out.)
Next day, preheat the oven to the lowest possible setting (mine gets down to about 170°F/80°C). Place chopped leek on a parchment or silicone lined baking sheet. Place in the oven for 4-5 hours until the leek bits crunch in your hand. Be careful not to let the white parts burn. They will probably turn brown (mine totally did) and that’s okay. Let cool completely before transferring to a lidded jar or grinding into a leek powder.
To make leek powder:
Place dried leek pieces in a high speed blender or spice grinder and pulse until you reach your desired consistency. Store in a lidded jar.