Have you ever noticed that prunes are black, but plums aren’t? Prunes being dried plums, you’d think they’d resemble each other. But there’s a reason for that.
The down side is that, at 20% moisture, a prune is a bit like a fruit leather–sort of like dried apricots. Turning them into something you could bake into a cake requires a long period of cooking, or stewing.
In the 1930s, companies started selling “tenderized” prunes, which were dried plums with a bit of moisture added back to bring them to about 30% moisture. As the ad above says, these cooked “in half the time.” One slight side-effect: to prevent the partially rehydrated plums from molding, an acidic salt is added–potassium sorbate. It turns the prune black.
Here’s a similar recipe from the October 19, 1916 edition of the Spirit Lake (Iowa) Beacon:
1 cup sugar
Whites of eggs added last, a few nut meats if desired.
–Mrs. Edward Bridson.
For more on rationing and prunes, see the recipe for prune cake from Canby, Oregon.
From the box of A.D. from Lutz, Florida, by way of Pennsylvania in the 1940s, and originating in Ohio in the 1920s.
1/3 cup butter
1-1/8 cup sugar
2 egg yolks
1 whole egg
5 Tbsp. sour cream or milk
1-1/8 cup stewed prunes
1/4 tsp. lemon extract
1-1/2 cup flour
3/4 tsp. baking powder
1 tsp. baking soda
1/4 tsp. salt
1 tsp. each cloves, nutmeg, and cinnamon
1 cup chopped walnuts]
Cream 1/3 cup butter and 1-1/8 cup sugar. Add 2 egg yolks and one whole egg; 5 Tbsp. sour cream or milk; 1-1/8 cup stewed prunes, stoned; 1/4 tsp. lemon extract.
Sift 1-1/2 cup flour and 3/4 tsp. baking powder and 1 tsp. soda, 1/4 tsp. salt, and 1 tsp. each of cloves, nutmeg, and cinnamon. Then add one cup chopped walnuts.
Pour into layer cake pans and bake 30 minutes in moderate oven.
Put together with a white boiled frosting.