- sliced onions
- sliced leeks
- sea salt
On a metal baking sheet, spread a single layer of sliced onions and leeks. Place under the broiler and cook, turning once or twice, until fullycharred and crisp, about an hour.
Remove from the oven, cool, then pulverize in a food processor or Vitamix, or in batches in a spice grinder. Combine powdered ash with an equal amount of sea salt (smoked or plain) and pulverize once again. Store indefinitely in a tightly sealed container.