Gelatin became a popular foundation for many meals during the 1930s after the Great Depression because it was an inexpensive source of protein. According to The Oxford Encyclopedia of Food and Drink in America, close to a third of all cookbook recipes from this time period were gelatin-based.
A Jell-O dish with radishes, scallions, and a few tablespoons of vinegar wouldn't have been out of the ordinary at a festive meal. Some people continue to serve them up on Thanksgiving just because.
Gelatin was also popular in sweeter desserts. One example is the "spring basket dessert," which was advertised in The Ladies Home Journal in 1948.
Ambrosia recipes began appearing in publications towards the end of the 19th century, Serious Eats reported. It remains a holiday classic in some Southern homes, but is rarely seen elsewhere.
A 1948 ad in the Ladies Home Journal advertised creamed corn in a can as "something to try — smooth, creamy, with plenty of tender-skinned kernels to round out the good eating."
In a 1968 advertisement, Dr Pepper recommended serving "steaming hot" soda over lemon slices. It definitely is "something different" to offer Thanksgiving guests.
One of the delicacies in the collection was the "Cranberry Surprise," a holiday side dish that "blends the tartness of cranberries with the delicate creaminess of Hellman's Real Mayonnaise" with an extra dollop of mayonnaise on top to provide "the final distinctive flavor garnish."