Baked sweet potato cake
Baked sweet potato cake is a rustic homemade treat: steamed, mashed sweet potatoes are mixed with coconut milk, eggs and butter, then baked in a pan until the top is shiny and golden. The inside is smooth and chewy, with the natural sweetness of the potatoes and the rich aroma of coconut, while the edges around the pan turn irresistibly crisp and caramelized.
- Difficulty
- Easy
- Prep
- 40 min
- Cook
- 1 hr
- Rising or chilling
- 1 hr 30 min
- Total time
- 3 hr 10 min
- Method
- Oven-baked
Ingredients
Sweet potato batter
Glaze
Preparing the pan
Instructions
Step 1
Peel 600 g sweet potatoes, cut them into thick chunks and steam over medium heat for about 25 minutes. Steaming keeps the potatoes dry and makes them sweeter than boiling them in water. They are done when a chopstick slides through easily and the chunks are soft and crumbly.
Step 2
Heat the oven to 180°C, brush to taste vegetable oil over a 20 cm square pan and line the bottom with parchment paper. The parchment lets you lift the cake out in one piece, and the oil creates crisp golden edges along the sides of the pan. The pan is ready when the paper lies flat against the bottom.
Step 3
Put the hot sweet potatoes in a blender with 200 g coconut milk and 40 g unsalted butter and blend until very smooth. The heat of the potatoes melts the butter and blends it in evenly with no need to melt it separately. The mixture is ready when it is as smooth as cream, an even orange-yellow and free of fibers.
Step 4
Pour the sweet potato into a bowl, add 120 g granulated sugar, a pinch salt, 3 g vanilla extract and 100 g beaten eggs, mix well, then sift in 60 g glutinous rice flour and 40 g tapioca starch and stir until no dry flour remains. The glutinous rice flour and tapioca starch bind the cake so it cuts into neat pieces while staying chewy. The batter is ready when it is thick, falls slowly from the whisk and has no white streaks of flour.
Step 5
Pour the batter into the pan, smooth the top with a flat spatula and tap the pan on the counter a few times. A flat top helps the cake bake evenly and the glaze brown beautifully later. The pan is ready when the top is level with no large air bubbles rising.
Step 6
Bake on the middle rack at 180°C for about 45 to 50 minutes. A long enough bake drives off some of the moisture in the potatoes and sets the crumb. The cake is done when the edges pull away from the pan, the top has set and a toothpick inserted in the center comes out only slightly moist.
Step 7
Beat 18 g egg yolks and brush them evenly over the top, sprinkle with 10 g white sesame seeds, then raise the oven to 200°C and bake for 8 to 10 minutes more. The yolk creates a glossy golden top, and the sesame toasts crisp right on the cake. It is ready when the top is shiny golden brown and the sesame has turned ivory gold.
Step 8
Take the cake out, let it cool in the pan for about an hour and a half, then lift it out by the parchment and cut it into squares. The hot cake is still very soft and only firm enough to cut with sharp edges once cool. The pieces are right when the cut faces are smooth, chewy and orange-yellow and do not stick to the knife.
Equipment
- Oven
- Square pan
- Steamer
- Food processor
- Mixing bowl
- Spatula
- Kitchen scale
- Parchment paper
- Pastry brush
Tips
- Yellow- or orange-fleshed sweet potatoes give the prettiest color and sweetest flavor; with purple sweet potatoes you get a strikingly purple cake.
- The sweetness of sweet potatoes varies by season, so taste the mixture before adding the eggs and adjust the sugar.
- If the top browns too quickly while baking, lay a sheet of foil over it.
Storage
Covered, the cake keeps for one day at room temperature. You can wrap it in plastic wrap and refrigerate it for up to four days, then reheat it in the oven or a nonstick skillet to crisp the edges again.
Common problems and how to fix them
- The crumb is wet and gummy after cooling.
- The potatoes absorbed water while steaming or the cake was not baked long enough. Steam the potatoes on a dry steamer rack and bake ten minutes longer, until a toothpick comes out almost clean.
- The cake has a stringy, fibrous texture.
- The potatoes were not blended smoothly enough or were a fibrous variety. Blend longer or strain the mixture through a sieve before adding the flours.
This recipe is based on the common ratios for this bake and is written entirely in our own words.
