While we were in Guatemala, a chef welcomed us into his kitchen to teach us about Guatemalan cuisine. One of the details I found most compelling was his use of garlic and onion skin ash. Instead of tossing these skins in the compost or the stock bag, he chars them. Next, he finely grinds them, and uses the mixture as frequently as salt or pepper.
I haven’t gotten into that same habit (yet?), but I love to use the mixture when something needs an extra bit of smoky allium flavor. For inspiration, check out my pizza that combines this ash with goat cheese, caramelized onions, balsamic vinegar, and thyme.
You can honestly use this garlic and onion skin ash in just about any savory dish. It works as a finishing sprinkle on soups, veggies, or meats. It’s also great in sauces, where it adds some extra flavor. The only time I would avoid using it is when something already has a lot of smokiness or char. For example, don’t use it on oven-charred Brussels sprouts or in a soup that uses smoked paprika. If you do, you risk doubling up too much on the smokiness and creating a result that tastes burned.
- garlic skins
- onion skins
- Preheat the oven to 350 degrees Fahrenheit.
- Arrange the garlic and onion skins on a baking sheet. Make sure you’re using only the outer, dried skins — not the next layer of onion that has some moisture still.
- Bake the skins until very dark brown, about 30 minutes.
- Transfer the skins into a food processor. Get your fingers damp and flick just a tiny bit of water into the food processor. (This will help keep the skins from just flying around inside.) Process until the skins are finely chopped.