Answer: Lime Jell-O

You may have never stopped to think about this, but if you’re an American old enough to remember any of the 20th century (or young enough and raised in areas of the country where Jell-O is still quite popular), then you may have noticed something kind of odd when you stop to think about it. There are a lot of lime Jell-O based recipes floating around. Even though Jell-O makes tons of flavors—orange, strawberry, cherry, grape, lemon, pineapple, and more—lime is everywhere.

This isn’t a coincidence and is due in no small part to the introduction of the lime flavor at the same time that Jell-O was enjoying a meteoric rise in status as a must-have dinner option. Lime flavored Jell-O was introduced in 1930 and, thanks to an increasing interest in Jell-O combined with the novelty of the new flavor (as well as a healthy PR push by Jell-O owner General Foods designed to capitalize on the sudden must-have status of Jell-O as a dining option), Jell-O cookbooks focused on incorporating lime Jell-O into meal plans started popping up everywhere.

If you can imagine eating it, somebody somewhere imagined combining it with Jell-O—pasta, fish, vegetables, salad greens, you name it. Today, we think of “Jell-O salad” as a sweet fruit concoction full of berries and pineapple, but back when it was introduced, it was quite popular to gelatinize actual table salads—spinach, diced savory vegetables, and all. Among all the flavors, lime really took hold and, well into the 1950s, lime Jello-O based recipes were dinner staples across the country. Even today, it’s not unusual, especially if attending a meal hosted by someone older raised in the era of ubiquitous lime Jell-O dishes, to find a bit of wobbly green Jell-O in front of you.