Why Do We Add Marshmallows To Sweet Potatoes?

marshmallows added to sweet potato casserole
PHOTO: CAITLIN BENSEL; FOOD STYLIST: TORIE COX

Whether you’re hosting your first Thanksgiving dinner or your fifteenth, there are some staples that you probably should consider as musts as part of a traditional holiday spread. A turkey, naturally, plus a veritable cornucopia of signature sides, including mashed potatoes, dressing, green bean casserole, cranberry sauce, rolls, and sweet potato casserole—topped with pecans and marshmallows, of course.

Just one Southern state, North Carolina, grows about 60 percent of America’s sweet potato supply. So whether the casserole has origins in the South or not, we’re adopting it as a member of our culinary cannon and declaring sweet potato casserole a supremely Southern side. 

As far as the toppings for sweet potato casserole go, pecans, we can understand. The spuds and pecans share nutty notes. At the same time, the saltiness of the nuts play nicely with the aptly-named sweet potatoes. 

But as you assemble your casserole, have you ever stopped to consider why we shower the top with marshmallows? We tapped Beth Forrest, Ph.D., food historian and professor of liberal arts and food studies at the Culinary Institute of America in Hyde Park, New York, to teach us the backstory of this beloved duo.

Beth Forrest, Ph.D is a food historian and professor of liberal arts and food studies at the Culinary Institute of America

Sweet Potato Casserole With Marshmallows - Southern Living
CAITLIN BENSEL; FOOD STYLIST: TORIE COX

The Fascinating History Of Marshmallows

“Marshmallows have gone through quite the transformation in terms of ingredients and cultural uses,” explains Forrest.

“Marsh mallow” in its original meaning refers to the althaea officinalis plant. Historically, the sticky substance found in the roots, leaves, and flowers were all used for herbal tea. Forrest confirms that there is evidence dating back to ancient Egyptians calling for the use of this plant for medicinal purposes. 

“This continued in medieval Europe, and even up to the 17th and 18th century in Europe and the United States. If you search in books and treatises printed before 1880, it is found in pharmaceutical and medical writings and recommended for an array of ailments,” Forrest says.

Recipes for marshmallows start to pop up around this time. But rather than looking like the s’mores staples we know today, early marshmallow recipes focused on creating marshmallow syrup or lozenges designed to help potentially alleviate cold symptoms. 

The shape-shifting continued for decades, and by the time the influential Boston Cooking School Cookbook of 1896 debuted, “Marshmallow Paste” was used as a filling or frosting and made with sugar, milk, marshmallow, water, and vanilla. Just three years later, 1899’s Perfection in Baking showcased a marshmallow filling using gelatin, powdered sugar, glucose, cream of tartar, and vanilla or honeysuckle for flavor, Forrest adds.

Why We Add Marshmallows To Sweet Potatoes

While we certainly wouldn’t have had it on our Bingo card at the time, “the combination of marshmallows and fall vegetables is less surprising than one might assume,” says Forrest.

Several recipes in cookbooks from the past 400 years call for pairing potatoes with sugar. In medieval Europe, sugar was liberally added to savory dishes as a sign of wealth—and because humans then and now are genetically predisposed to seek out sweet foods.

Forrest nods to William Rabisha’s 1675 cookbook The Whole Body of Cookery Dissected, Taught and Fully Manifested, which instructs readers to make a “potato pye” by seasoning boiled sliced potatoes with nutmeg, cinnamon, ginger, raisins, dates, orange, citrus, butter, and sugar.

Sweet potatoes are different than white potatoes, though, and sugar and sweet spuds begin to appear together in literature soon after: The first cookbook printed in the U.S., American Cookery (1796) by Amelia Simmons, featured a sweet potato pudding made with sweet potatoes, apples, eggs, cream, nutmeg, salt, and sugar. It’s all starting to sound eerily familiar, right?

A Successful Combination

Most people point to a 1917 pamphlet by the Angelus Marshmallow Company as the first time sweet potatoes and marshmallows came together. This company is believed to be the first to commercially-produce and sell the squishy white marshmallows we know, roast, and snack on today. However, Forrest was able to dig up something even earlier: The May 1916 issue of Cooking Club Magazine printed in Goshen, Indiana, had a recipe with both marshmallows and sweet potatoes.

“Also in 1916, Mary Brown from Georgia contributed the recipe [Sweet] Potato Marshmallow Pudding to a community fundraising cookbook called At the Sign of the Rolling Pin,” Forrest says. “Mary noted, ‘this dish is used in the South with the vegetable dish,’ suggesting that the dish had been long in circulation before the Angelus Marshmallow pamphlet.”

That being said, the trend really exploded after the Angelus Marshmallow Company pamphlet was distributed far and wide.

“Who actually invented the first combination of sweet potatoes with marshmallows might be lost to the annals of history. But with its warming spices alongside the peak of sweet potatoes happening in late fall and winter, it has come to be an indulgent sign of Thanksgiving for more than 100 years,” says Forrest.

Now that you know a bit about the history of sweet potato casserole and its gorgeously-toasted cloud-like crown, celebrate this dream team this Thanksgiving—or any time of year—with our recipes.