When you think of the origins of the atomic bomb, chocolate cake as an important contribution to its success probably doesn’t come to mind. Think again. If Edith Warner’s famous dessert hadn’t fed the isolated scientists working on the Manhattan Project, history might have taken a different turn.
Edith Warner’s House at Otowi Bridge

Edith Warner was born in 1893 in Pennsylvania. She moved to New Mexico in 1922–depending on the source–for health reasons, to teach at the Los Alamos Boys’ School, or because she simply loved the area. At any rate, she wanted to live life on her own terms. She lived in a tiny adobe cottage next to the Rio Grande, at the foothills of the Jémez Mountains…near Los Alamos. In 1924, a single-lane suspension bridge, called Otowi Bridge, was built across the Rio Grande, next to her home. Edith decided to support herself by opening a teahouse to serve the occasional passersby.
Life was calm for twenty years. Edith was the neighbor and friend of the nearby Indians of San Ildefonso Pueblo. She developed a lifelong relationship with one of the elders, Atilano Montoya. When a railroad–the Chili Line–was built to reach Los Alamos, she became the area’s postmaster and handled supplies for the boys’ school.
Chocolate Cake: Butter and chocolate always available
Then came Robert Oppenheimer. He had also visited the Parajito Plateau–part of the mountain range–in 1922. In fact, he’d met Edith Warner in 1937 and had even stopped at her teahouse. When it came time to start the Manhattan Project, he wanted a remote location. And he knew the perfect place…Los Alamos.
The story of the secret location (it wasn’t on the map and only had a single P.O. Box for the entire project) and the history of the Manhattan Project are worth learning. (I recommend The Making of the Atomic Bomb by Richard Rhodes. He won the Pulitzer Prize for his book.) Scientists, and their families, were secluded on “The Hill,” as the site was called. (Watch the Atomic Heritage Foundation’s short video, “Life’s Going to Change,” the story of Oppenheimer and Warner here.) Trips to Santa Fe, 34 miles away, were rare; a pass was required to leave.
Edith’s teahouse became the place for dinners and socializing. Some called it the “cultural crossroads.” She and Atilano were serving people who would later earn Nobel Prizes. (Enrico Fermi, called “Mr. Farmer” on the project, won his Nobel Prize in 1938.)
Oppenheimer recognized that his research and project teams needed to feel appreciated…and well-fed. He arranged for Edith to have access to otherwise-rationed supplies to make meals for the families. She was given as much butter and cocoa as she needed to make her famous chocolate cake. Reservations for dinner were required and booked weeks in advance.



Everyone on the project was forbidden to discuss it with anyone else. But Edith was a quick study and sensed what was going on. She wrote to a friend, “These civilians are a most remarkable combination of seriousness and boy-like enthusiasm. I sense their enormous determination to win the war, although they talk only roundabout of their work, using odd and amusing terms such as ‘gadget,’ ‘shakes,’ and ‘jerks.’ Yet they often express an excitement about what they’re doing, as if they’re on to something … magnificent. Mischievous boys engaged in playful exploration, yet grown men.” Indeed. When the bombs fell, the pieces quickly fell into place for her.
After the war, Edith and Atilano were eager for a return to peace and quiet. But in 1947, they got news that a steel highway bridge was not only going to replace the simple structure outside her home, but would pass through the front yard. They moved half a mile away and built a new adobe home…with the combined help of Indians and the scientists and their wives, under the direction of Atilano.
Edith died of cancer in 1951. Atilano followed her a few years later. In 1975, the Otowi Historic District became listed on the National Register of Historic Places.
Going to New Mexico? Visit the Bradbury Science Museum in Los Alamos to learn more about the Manhattan Project. It’s open every day of the week, except Monday mornings. Information here.
The recipe: Easy to make!
Now…for that chocolate cake. This is the original version, taken from her letters. The letters are archived at the Los Alamos Historical Society.



Edith Warner’s Chocolate Cake
Makes one layer or one small loaf. Heat oven to 250 degrees.
Melt over hot water: 1-1/2 ounces Baker’s unsweetened chocolate squares,
with 3 Tablespoons butter
Pour over: 1 cup sugar
Add: 1 cup sifted flour, 1/2 teaspoon salt, 2 teaspoons baking powder
BEAT: 2 minutes with a rotary egg-beater
Add: 3 unbeaten eggs
BEAT: 2 more minutes
Directions: Pour into greased and floured loaf pan. Bake in a slow oven (250 degrees), raising heat to 300 degrees, for one hour, or until done. Begin at 250 degrees, and increase by 25 degrees every 15-20 minutes. A shallow pan will require shorter period.
Chocolate Frosting
Sift into a bowl: 1/4 cup powdered sugar, 2 heaping Tablespoons cocoa, pinch of salt
Melt: 2 slices of butter and pour over above. (NOTE: Equivalent: 2 Tablespoons)
Directions: mix together. If necessary, add a few Tablespoons of coffee to reach consistency for spreading.



If you’re interested in learning more about Edith Warner and her life during the Manhattan Project, read The House at Otowi Bridge: The Story of Edith Warner and Los Alamos by Peggy Pond Church. Peggy lived on the Pajarito Plateau during her childhood. After attending Smith College, she returned to teach at Los Alamos Ranch School, which was founded by her father
Dr. Phillip Morrison’s letter to Edith, written in 1945, is included in the book: “…We had to learn again in all its meaning how strong is the bond between science and the life of men…What was new was the life around us that we began to share… Not the smallest part of the life we came to lead, Miss Warner, was you. Evenings in your place by the river, by the table so neatly set, before the fireplace so carefully contrived, gave us a little of your assurance, allowed us to belong. We shall never forget.”
The folks at the New Mexico History Museum note that there is a chocolate cake recipe in the book, but Edith Warner’s original is better.
More food and history?
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Pasties: Delicious “Yooper” Tradition
The Original Brownie Recipe–From Chicago’s Palmer House Hotel
Spanish Tortilla: Make It at Home!
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