Soft and fluffy kuih puteri ayu made with purple sweet potato and grated coconut are steamed to perfection are perfect for snacks or light desserts.
Purple sweet potatoes (ubi ungu) is one of the most popular sweet potatoes being used to make desserts, cake, and in cooking in Asia. The vibrant purple hue is pleasing to the eyes. A while ago I made these kuih puteri ayu pandan, which is the classic and original flavor. I happened to have purple sweet potatoes at home and decided to make kuih puteri ayu with them.
Color change with purple sweet potatoes
It is not unusual for the natural purple colors in sweet potatoes to change color in baking or cooking. You may not end up with purple color. You may get bluish/greenish hue instead. The pigment anthocyanin will react with anything alkaline or when the yellow of yolks are added in. I added some purple food gel to “fix” this problem. It’s not necessarily a problem, just more of a visual. If you don’t mind it, you don’t have to add purple food gel. The taste of the cake doesn’t change or spoil because of the color change.
What type of purple sweet potato to use?
Stokes purple sweet potatoes are the best to use as they aren’t as dry. Other varieties such as Okinawan purple sweet potatoes, Filipino and Charleston purple sweet potatoes are very dry, starchy, with a slight bitter after taste. You can also use Filipino Ube yam (not a sweet potato), which is more of pinkish purple instead of deep purple like purple sweet potatoes
1. Please make sure the eggs are at room temperature
2. Beat the eggs with sugar until ribbon stage. This is the key to fluffy and light texture cake
3. Steam the cake over medium heat
How to store kuih puteri ayu ubi ungu
1. Let the kuih cool down completely
2. Transfer to an air-tight container and store at room temperature for 24 hours. Anything longer, the coconut may spoil, especially if it’s humid where you are
3. They can be kept in the fridge for another day or two. They may hardened the longer you keep them in the fridge
4. Simply reheat with moist heat like in the steamer for few minutes until warm and they will be as good as new
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You may also like this pandan puteri ayu
Kuih Puteri Ayu Ubi Ungu / Putu Ayu (Purple Sweet Potato Puteri Ayu)
Food coloring (optional):
- purple food gel
- Peel the potato and cut into smaller pieces and steam until they are fork tender and can be easily mashed. Transfer the purple sweet potato, coconut cream, and food coloring in a blender and blend until smooth. It will be thick, but smooth. I get a better result when I do this part first before combining them into the batter. Set aside.
- In the same steamer, steam the grated coconut with 1/4 tsp of salt for 10 minutes. Set aside
- Brush the puteri ayu mould with some cooking oil on the base and the side of the mould. If you don't have one, you can use small muffin cups. Portion out the steamed grated coconut into the muffin cups. Make sure to PRESS the coconut down firmly with your fingers on the base of the cups so when you invert the cake the grated coconut won't come "loose"
- Place the eggs and sugar in a mixing bowl. I used a stand mixer with whisk attachment. Beat on medium speed for 5 minutes and then increase to high speed and beat for another 10-15 minutes or until they have reached ribbon stage. When you lift the whisk up, the batter will drop down leaving a trail that remains visible for 10 seconds or so before dissolving back into the batter. The volume will triple up too. Reduce the speed to medium and in mashed purple yam, coconut milk mixture and stir until all mixed in.
- Add few drops of purple food gel if using. Please note that without food gel/coloring or extract, the natural purple color may change into greenish/bluish after baking and this is normal. Reduce the speed to low and add vanilla, salt, and all-purpose flour. The idea is just to mix in the flour. You don't want to overbeat the flour. Turn off the mixer and use a spatula to fold in the rest of the flour until no more pockets of flour are visible
- Portion out the batter into the muffin cups you have prepared with coconut earlier, about 3/4 cup full. Steam for 15 minutes over medium heat
- Remove from the steamer and wait for 5 minutes before removing from the cups. If necessary, run a knife at the side of the cup to loosen the cake. They shouldn't be very sticky or difficult to remove. Invert into a serving platter. The coconut portion should be on top as shown in the photos. Serve warm or room temperature
- You can store the rest in the refrigerator in an air-tight container up to 3 days. Just reheat in the microwave for few seconds (I'm not sure because we don't use microwave) or in the steamer for 5 minutes