HONG KONG, Dec 12 — Wicked star and singer Ariana Grande is the latest celebrity to sing praises of Pei Pa Koa, a traditional Chinese herbal syrup, for its soothing effects on vocal cords.

Here’s a simple elderberry syrup recipe that will keep for a couple of months in your refrigerator. You can dole it out in spoonfuls just like cough medicine, or you can stir it into your ...