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The week my father dug up the first sweet potatoes of the fall, there were always more than we could eat at supper, and my mother baked the leftover ones into a pound cake. My father ate the first slice standing at the kitchen counter, still in his work boots, and told her it was the only cake he had ever eaten that tasted like supper and dessert at the same time. The cake came out dense and moist, a deep orange-gold all the way through, with a fine tight crumb.
The one rule she never broke was that the sweet potatoes are baked, not boiled. Boiled sweet potatoes soak up water, and that water goes into the batter and makes the cake heavy, gummy and pale. Baked whole in their skins, the sweet potatoes lose water instead of gaining it, and their sugar caramelizes until it runs out in dark sticky drops. That is where the color and the deep flavor come from. The rest is a classic Southern pound cake: butter and sugar creamed until fluffy, eggs beaten in one at a time, a little buttermilk, cinnamon and nutmeg. The brown butter glaze goes on while the cake is warm and soaks into the crust.
Why this sweet potato pound cake works
- Baked sweet potatoes. Baking concentrates the flavor and drives out water, so the cake is moist without being gummy.
- Cooled mash. The mashed sweet potato goes in at room temperature so it does not melt the creamed butter and sugar.
- Long creaming. Five full minutes of beating the butter and sugar builds the air that gives a pound cake its tight, even crumb.
- A low oven. At 325 degrees the tall cake bakes through to the middle before the outside gets too dark.
- Brown butter glaze. Browned butter tastes toasty and nutty, which is exactly what sweet potato and cinnamon want.
Ingredients
Makes one 10 inch tube or Bundt cake, about 16 slices. The measurements are in US cups with grams in brackets.
For the cake
- 2 medium sweet potatoes, enough for 1 1/2 cups mashed (about 360g mashed)
- 3 cups all-purpose flour (375g)
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon fine salt
- 2 teaspoons ground cinnamon
- 1/2 teaspoon ground nutmeg
- 1 cup unsalted butter, softened (226g)
- 2 1/2 cups granulated sugar (500g)
- 5 large eggs, at room temperature
- 1/2 cup buttermilk (120ml), at room temperature
- 2 teaspoons vanilla extract
For the brown butter glaze
- 4 tablespoons unsalted butter (56g)
- 1 1/2 cups powdered sugar (180g)
- 2 to 3 tablespoons milk (30 to 45ml)
- 1/2 teaspoon vanilla extract
- Pinch of fine salt
Choose orange-fleshed sweet potatoes, the kind sold as garnet or jewel. Bake them whole the day before if you like and keep the flesh covered in the refrigerator; let it come back to room temperature before mixing.
How to make sweet potato pound cake
Bake the sweet potatoes
- Heat the oven to 400 degrees (200°C). Prick the sweet potatoes a few times with a fork and set them on a foil-lined baking sheet. Bake 50 to 60 minutes, until they are completely soft and some syrup has leaked out and darkened on the foil.
- Split them, scoop out the flesh and mash it smooth with a fork or potato masher. Measure 1 1/2 cups (about 360g) and let it cool to room temperature.
Make the cake
- Lower the oven to 325 degrees (165°C). Grease a 10 inch tube or Bundt pan very well with soft butter and dust it with flour, tapping out the extra.
- Whisk the flour, baking powder, baking soda, salt, cinnamon and nutmeg together in a bowl.
- In a large bowl, beat the butter and sugar with a mixer on medium-high for a full 5 minutes, until pale and fluffy.
- Beat in the eggs one at a time, mixing well after each. Beat in the cooled sweet potato and the vanilla.
- On low speed, add the flour mixture in three parts, alternating with the buttermilk in two parts, starting and ending with flour. Mix only until no flour shows.
- Spread the batter in the pan and tap the pan on the counter to settle it. Bake 70 to 80 minutes, until a long wooden skewer pushed into the thickest part comes out clean or with a few moist crumbs. Start checking at 65 minutes.
- Cool the cake in the pan for 15 minutes, then turn it out onto a rack.
Glaze it
- Melt the butter in a small light-colored pan over medium heat and keep cooking, swirling, until the foam turns golden and the bits at the bottom are brown and smell like toasted nuts, 3 to 5 minutes. Pour it into a bowl right away.
- Whisk in the powdered sugar, 2 tablespoons milk, the vanilla and the salt until smooth, adding the last spoon of milk if it is too thick to pour. Spoon the glaze over the warm cake so it runs down the sides. Let it set 30 minutes before slicing.
Tips that make the difference
- Never boil the sweet potatoes for this cake. Boiled flesh carries too much water and gives a heavy, pale cake.
- Grease every ridge of the pan with soft butter, not spray alone. Pound cakes stick where they are not greased.
- Test with a long skewer in the thickest part, near the middle tube. A toothpick is too short to reach the center of a tall cake.
- Pour the glaze while the cake is warm, not hot. A hot cake drinks the glaze completely; a warm one lets it set in drips.
Variations
- Pecan. Fold 1 cup (115g) of chopped toasted pecans into the finished batter and scatter a few more over the glaze.
- Loaf pans. Divide the batter between two greased 9x5 inch loaf pans and bake 55 to 65 minutes.
- Cream cheese glaze. Beat 2 ounces (56g) of soft cream cheese with the powdered sugar and milk instead of the brown butter.
Storage and make-ahead
Keep the cake covered at room temperature for up to 4 days. Pound cake is better on the second day, when the crumb has settled and the flavor has deepened.
To freeze, wrap the unglazed cake or single slices tightly in plastic wrap and then foil and freeze for up to 3 months. Thaw on the counter, still wrapped, and glaze before serving.
Frequently asked questions
How long does a sweet potato pound cake take to bake?
About 70 to 80 minutes at 325 degrees in a 10 inch tube or Bundt pan. Start checking at 65 minutes with a long skewer in the thickest part. It is done when the skewer comes out clean or with a few moist crumbs and the top springs back.
Can I use canned sweet potatoes?
You can use plain canned sweet potato puree, not the kind packed in syrup. Cook it in a pan for a few minutes, stirring, to drive off some water, then cool it. Freshly baked sweet potatoes still give the deepest flavor.
Why did my pound cake sink in the middle?
Usually the cake came out too early, the oven door was opened in the first hour, or the butter and sugar were not creamed long enough to hold the air. Use the skewer test and keep the door shut.
Bake the sweet potatoes, let them cool, and give the butter and sugar their full five minutes. The cake does the rest, and the first slice belongs to whoever dug the sweet potatoes.
Sweet Potato Pound Cake with Brown Butter Glaze
Old-fashioned sweet potato pound cake: baked (never boiled) sweet potatoes, butter, sugar, eggs, buttermilk, cinnamon and nutmeg, baked in a tube pan at 325 degrees for about 75 minutes and finished with a warm brown butter glaze.
Ingredients
- 2 medium sweet potatoes, enough for 1 1/2 cups mashed
- 3 cups all-purpose flour
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon fine salt
- 2 teaspoons ground cinnamon
- 1/2 teaspoon ground nutmeg
- 1 cup unsalted butter, softened
- 2 1/2 cups granulated sugar
- 5 large eggs, at room temperature
- 1/2 cup buttermilk (120ml), at room temperature
- 2 teaspoons vanilla extract
- 4 tablespoons unsalted butter
- 1 1/2 cups powdered sugar
- 2 to 3 tablespoons milk
- 1/2 teaspoon vanilla extract
- Pinch of fine salt
Instructions
- Heat the oven to 400 degrees (200°C). Prick the sweet potatoes a few times with a fork and set them on a foil-lined baking sheet. Bake 50 to 60 minutes, until they are completely soft and some syrup has leaked out and darkened on the foil.
- Split them, scoop out the flesh and mash it smooth with a fork or potato masher. Measure 1 1/2 cups (about 360g) and let it cool to room temperature.
- Lower the oven to 325 degrees (165°C). Grease a 10 inch tube or Bundt pan very well with soft butter and dust it with flour, tapping out the extra.
- Whisk the flour, baking powder, baking soda, salt, cinnamon and nutmeg together in a bowl.
- In a large bowl, beat the butter and sugar with a mixer on medium-high for a full 5 minutes, until pale and fluffy.
- Beat in the eggs one at a time, mixing well after each. Beat in the cooled sweet potato and the vanilla.
- On low speed, add the flour mixture in three parts, alternating with the buttermilk in two parts, starting and ending with flour. Mix only until no flour shows.
- Spread the batter in the pan and tap the pan on the counter to settle it. Bake 70 to 80 minutes, until a long wooden skewer pushed into the thickest part comes out clean or with a few moist crumbs. Start checking at 65 minutes.
- Cool the cake in the pan for 15 minutes, then turn it out onto a rack.
- Melt the butter in a small light-colored pan over medium heat and keep cooking, swirling, until the foam turns golden and the bits at the bottom are brown and smell like toasted nuts, 3 to 5 minutes. Pour it into a bowl right away.
- Whisk in the powdered sugar, 2 tablespoons milk, the vanilla and the salt until smooth, adding the last spoon of milk if it is too thick to pour. Spoon the glaze over the warm cake so it runs down the sides. Let it set 30 minutes before slicing.
