Traditionally used as a dipping sauce for shabu-shabu (Japanese hot pot meals) or tempura, think of ponzu as a citrus-flavored soy sauce, only way more complex than what would happen if you dumped lemon juice in some Kikkoman. It's made when yuzu fruit or sudachi -- a round, green mandarin -- is cooked down with other aromatics like bonito fish flakes, seaweed, mirin, and rice wine. Soy is added, which yields a final product packed with rich umami flavor and full of tang thanks to the citrus and vinegar. Oh, and nod only does it make just about anything you put it on 1,000% times more flavorful, it's also a kick-ass marinade.
Pair it with like ahi tuna, salmon, trout, snapper for best results since fish and citrus belong together, though it works pretty well on chicken, too. Its unique flavor profile works with many different types of cuisines, so you can take it beyond Japanese recipes and throw it in just about anywhere you could use a punch of rich umami and citrus -- check out these ponzu-marinated carne asada tacos -- or in its simplest form over some freshly grilled seafood.
And it's widely available, so you won't have to scour to find it... though the ubiquity means some brands are better than others.
"My favourite is the Higashimaru brand," says chef Hana Etsuko Dethlefsen, culinary instructor and author of Let's Cooking: Japanese Cooking at Home, Vol 1. "If you can't find that, the Mizkan brand is usually easier to find."
There's also this incredibly addicting looking Yuzu It sauce, which is "essentially a yuzu-chili hot sauce. It is more versatile, mild and user-friendly than traditional yuzu kosho," says Hart Lowry, executive chef at Hojoko in Boston.
If you're looking for a more refined product, you can always make your own, too. Chef Hiroyuki Naruke (aka Chef Hiro) at Q Sushi in Los Angeles recommends that you buy "any brand that is a basic blend, and blend it with kombu seaweed and bonito flake. Let it wait a few days to marinate. This will make your ponzu taste better by adding in the necessary flavors."