I love the idea of purple potatoes. I know, I know: they’ve been around forever and are far from uncommon — but they bring a welcome whimsy to a menu, in my view. Maybe it’s their unexpected burst of color, or their superbly syllabic name. Whatever the appeal, it lured me into purchasing a few too many pounds at the market recently. And it wasn’t long before the potatoes’ mild but earthy flavor whispered of dessert potential.
I imagined grating them into a carrot-cake-like batter, and knew they’d match nicely with a generous scoop of ginger. Tangy orange zest and mellow turbinado sugar would be musts, as would molasses — which is featured both in the cakes and frosting. (I’ve since wondered why I never thought of adding molasses to cream cheese frosting before; it tastes like velvety gingerbread cheesecake on a spoon — ahem, I mean, on cake!) While the potatoes lose their vivid color in the process, they take on a vibrant new life in the form of tender, rich, and splendidly balanced cupcakes: a perfect fall or winter treat.
Purple Potato Cupcakes [makes 16-18 standard sized cupcakes]
FOR THE CUPCAKE BATTER:
• 1 medium orange
• 8 ounces purple potatoes (from about 5 small potatoes), measuring about 1.5 cup grated
• fresh ginger root to grate into 1 tablespoon
• 2 eggs
• 2/3 cup vegetable oil
• 1/4 cup molasses (warmed slightly for easy pouring, if desired)
• 1 tablespoon pure vanilla extract
• 2/3 cup turbinado sugar
• 1.25 cups all purpose flour
• 1 teaspoon baking soda
• 1/2 teaspoon salt
• 2 teaspoons dried ground ginger
• optional: 2/3 cup raisins and/or chopped walnuts, preferably toasted
Preheat oven to 350 F. Line muffin tins with 16-18 paper liners. Rinse, dry, and finely zest the orange peel; set zest aside. Juice the orange, remove any seeds, and measure out 2 tablespoons juice. Set aside. Wash and dry potatoes; grate with a standard size (large hole) grater to make 1.5 cup grated, moderately packed, weighing 8 ounces. Using a very small, sharp grater such as a Microplane, grate the ginger until you have 1 packed tablespoon grated (see tip below*); set aside.
In a large bowl, beat eggs and oil until smooth. Beat in the molasses and vanilla. Add the sugar and stir until evenly dispersed. Sift flour, baking soda, salt, and ground ginger over the bowl. Begin to stir, alternately adding the 2 tablespoons of orange juice. Fold in the grated potato, orange zest and fresh ginger, mixing until incorporated. If using, fold in the chopped nuts and/or raisins.
Fill the lined cups of the muffin pans 1/2 to 2/3 full. Bake for about 15 minutes, just until a toothpick inserted in the center tests clean, with no wet batter. Remove from oven and let sit in pan just until cool enough to handle, then transfer to wire racks or a towel on your countertop. Let cool completely before frosting.
• 14 ounces cream cheese, softened
• 1/4 cup (2 ounces) butter, softened
• 1-2 tablespoons molasses, to taste (warmed slightly for easy pouring, if desired)
• 2 teaspoons dried ground ginger
• 1.25 cup powdered sugar
• 1/4 teaspoon salt (omit if using salted butter)
Beat cream cheese and butter until completely mixed. Add molasses and beat until evenly incorporated. Sift ginger, powdered sugar, and salt over the bowl. Beat until smooth, occasionally stopping to scrape sides and bottom of bowl with a rubber spatula. Transfer frosting to a pastry bag, and pipe it onto the cupcakes. If desired, decorate with sprinkles or more turbinado sugar. The texture of these cupcakes is best at room temperature, but if not eating within a few hours, store covered in the fridge for up to three days.
With their spiced, seasonal flavors and succulent texture, purple potato cupcakes are a celebration of unexpected decadence. The potato shreds offer gentle hints of an earthy, almost mineral taste, which is complemented perfectly by the dark molasses, warm ginger, and sweet orange. The dreamy frosting is smooth and addictive, with cream cheese and molasses proving to be a perfect pair. Carrot cake’s striking new cousin has arrived, and I think you’ll want it to stick around.
Maybe next time… I love the play of flavors in these cupcakes, but I do think they’d welcome other spices, either alongside or instead of the ginger (cinnamon, nutmeg, cloves…). Similarly, feel free to use demerera or brown sugar in place of the turbinado. Dried cranberries would add some seasonal flair swapped in for the optional raisins, as would hazelnuts or pecans instead of walnuts. I trust that this recipe would work nicely as a cake instead of cupcakes; just be sure to adjust the baking time accordingly.
*Grating fresh ginger can be tricky. I find it helps to start with a chilled or frozen ginger root, and to cut a long rectangle out of it, which will also remove the peel. I use a sharp, fine grater such as a Microplane, and hold the ginger rectangle in one hand and grater in the other, over a plate. Press the tip/narrow side of the ginger very firmly against the grater, and push back and forth quickly. Don’t expect the outcome to be dry or separated; it will most likely look like ginger mush, which is perfectly fine for most baked goods.