Whenever I go to Trader Joe's, I rarely walk out of there without buying at least half a dozen things that weren't on my shopping list. This citron spread was one of those products that caught my eye.
I've been using citron and yuzu to refer to the same fruit but after doing some research, I was surprised to discover that yuzu and citron are actually two different types of citrus. Yuzu (Citrus ichangensis x Citrus reticulata var. austera) is a cold hardy Asian citrus fruit that originated in China and then introduced to Japan and Korea. Citron (Citrus medica) on the other hand, is a different species that most likely also originated in Asia, but was subsequently spread throughout the Mediterranean. I was searching for the difference in flavor between the two fruits but it was difficult to find a comparison because many people, like myself, and resources use the names interchangeably. Even my jar says "Citron (Yuzu) spread", so now I'm not sure whether it's made with citron or yuzu. My guess is that the flavors are comparable. Yuzu has been a part of Japanese and Korean cuisine for quite some time but recently it has come to the attention of the Western food world and is now all the rage.
Yuzu is rarely eaten as a fruit but both the juice and zest are prized in cooking. The fruit bears very little juice, so it's very precious. The tart lemon-like juice with hints of lime, grapefruit, and pine forms the base of the Japanese dipping sauce, ponzu. The powerfully aromatic zest is used as a garnish on soup. It is also working its way into many sweet applications like cakes and sorbets. A spoonful of yuzu marmalade, similar to the spread I bought, is swirled into hot water to make a Korean drink called yuja cha, used as a remedy for the common cold.
Fresh yuzu are about the size of a small orange and are in season from November to May and can be found at at Japanese or Asian markets but they will be rather pricey ($3 - $4 each). The bottled juice can also be found at Asian markets.
So far I've used it as a glaze on scallops and as a filling in Asian rugelach. As Wandering Chopsticks suggested, it would be great on fish as well. And to satisfy your sweet tooth, Tartelette has wonderful yuzu recipes like this cheesecake or berry salad.