Purple Sweet Potato Tapioca Pudding (Sago)

I have been meaning to create a purple sweet potato version of my mango tapioca pudding (aka mango sago) for a long time. The inspiration struck when my mom was showing me how to make tapioca mooncakes with a purple sweet potato filling (recipe coming soon). The color of cooked Hawaiian sweet potatoes looked so beautiful that I thought it would add great color to a tapioca pudding. After a few experiments, I’m happy to bring you this purple sweet potato tapioca pudding that is both a delight to behold and to eat!

COOKING NOTES FOR PURPLE SWEET POTATO TAPIOCA PUDDING

SAGO VS TAPIOCA PEARLS

Whether this style of dessert should be called “tapioca pudding” or “sago” has been a hotly debated topic in the comments section of one of my videos on TikTok. In Asian dessert shops, and indeed most recipes online, these pudding-like desserts that use small tapioca pearls are often called “sago.” What I learned during my research, however, is that genuine sago and tapioca pearls are not the same thing. 

As cookbook author Pailin Chongchitnant explains, sago are brown pearls derived from starch inside the trunks of sago palm trees. Tapioca pearls, on the other hand, are usually derived from cassava root, which lends to the white color of the pearls. Pailin has great photos that illustrate how sago and tapioca pearls differ in appearance. Cassava grows much faster than sago palm trees, which is why tapioca pearls are less expensive and more readily available than sago. Consequently, most sago recipes use tapioca pearls to imitate genuine sago.

Because sago and tapioca pearls are two different things, I’ve generally called these desserts “tapioca pudding.” It’s also a closer translation of what this dessert is called in Chinese, 西米露. (In Cantonese, 西米露 is pronounced sai mai lo; in Mandarin, it’s xi mi lu.) However, I acknowledge that many people call these desserts “sago,” which is why it’s also in the name of this recipe. 

COOKING TAPIOCA PEARLS

When cooking small tapioca pearls, make sure to bring the water to boil before adding the pearls to the saucepan. Do not add the tapioca pearls when the water is still cold because the tapioca pearls can melt together (see photo below). 

The first time I tried making mango tapioca pudding, I added the pearls before the water boiled and the pearls congealed into a giant mass. Learn from my mistake: wait until the water reaches the boiling point before adding the tapioca pearls. 

You’ll cook the pearls for about 15 minutes over medium-high heat. After 15 minutes, the exterior of the pearls will look translucent and the center will have tiny specks of white color (see photo above, left). Turn off the heat, cover the pot with the lid and let the pearls sit for another 10 to 15 minutes, until they turn completely translucent (see photo above, right). 

Once the pearls have turned translucent, drain and rinse them under cold water. Then, transfer the cooked pearls to a large bowl filled with cold water (ice water or cold tap water is fine). This will help cool off the pearls further. Let the pearls sit in the water for a few minutes until you prep the other ingredients.

STEAMING PURPLE SWEET POTATOES

For the puree, I like to use Hawaiian (or Okinawa) purple sweet potatoes with pale yellow skins. I find that Hawaiian purple sweet potatoes have better flavor than the ones with orange/brown skins, like the Stokes purple sweet potato. I usually find Hawaiian purple sweet potatoes in Asian grocery stores. 

One important note: Hawaiian sweet potatoes are not the same as ube or taro. Ube is a type of yam that has a rough bark-like brown skin. You can read more about ube versus purple sweet potatoes here. 

Steam several sweet potatoes for 25 to 30 minutes, until you can easily pierce the flesh with a fork. I tried roasting the sweet potatoes during one of my test batches, and the roasting process browned the sweet potatoes too much. You need the sweet potatoes to look vibrant purple to give the puree its nice lavender color. You can also speed up the steaming process by slicing the sweet potatoes before steaming. 

Let the sweet potatoes cool slightly before peeling them. You’ll need about 3/4 cup of mashed sweet potatoes, which is about 2 medium-sized sweet potatoes. Slice the remaining sweet potatoes into small cubes, which you’ll mix into the tapioca pudding later.

MAKING SWEET POTATO PUREE

Heat some milk and coconut milk in a saucepan. For a dairy-free version, swap the milk with oat milk. When heating the milk, do not cover the saucepan with a lid as the milk boils over very easily and you’ll end up with a big mess. Right when the milk comes to a boil, turn off the heat. Add some honey, stir, and let the milk cool for 5 to 10 minutes.

I should note that it’s not completely necessary to boil the milk. When I developed the recipe for my mango tapioca pudding, I noticed that the batches made with unboiled milk started to turn gray after a few hours. However, the mango puree tended to hold its golden color better when I used boiled milk. That’s why I also recommend boiling the milk here, to ensure that the puree maintains its lilac hue. 

Pour the warmed milk into the bowl of a high-speed blender. Add the mashed sweet potatoes to the blender and blend everything until smooth. The puree will taste very sweet at this stage, so wait until you add the tapioca pearls before assessing the overall sweetness of the pudding.

FINISH TAPIOCA PUDDING

Drain the tapioca pearls and drizzle 2 tablespoons of honey over the pearls. Toss to coat the pearls with the honey. 

Add the tapioca pearls to the bowl with the sweet potato puree and stir. I like adding cubed sweet potato for additional texture and sliced strawberries for some sweet and lightly tart flavor. I think the tapioca pudding will taste great with longan as well! Taste the tapioca pudding and add more honey, if necessary.

You can eat the purple sweet potato tapioca pudding right away. However, I find it more refreshing when I chill it for 1 to 2 hours before serving.

CAN YOU COOK THE TAPIOCA PEARLS AHEAD?

Yes! If you’re planning to cook the tapioca pearls a day ahead, refrigerate the cooked pearls. The pearls will clump into a giant mass overnight. To loosen the pearls, bring a pot of water to boil and add the tapioca pearls. Use a skimmer or a flat spatula to break up the clumps of pearls. They should come apart in a few minutes.

CAN YOU PREPARE THE PUREE AHEAD?

Although you can steam the sweet potatoes a day or two ahead, I don’t recommend making the puree a day ahead. The puree loses its vibrancy the next day, so it’s best to make it the day you want to serve the tapioca pudding.

HOW LONG DOES THE PURPLE SWEET POTATO TAPIOCA PUDDING LAST?

The tapioca pudding is best the day it’s made. It’s still delicious the next day, but the color of the pudding won’t look as vibrant. Try to eat the pudding within 2 days as the pearls tend to dissolve over time and the color loses its vibrancy after that. The pudding thickens overnight, so you may want to drizzle more coconut milk into the pudding to loosen it up before serving.

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Servings: 4

Author: Lisa Lin

Purple Sweet Potato Tapioca Pudding (Sago)

This tapioca pudding gets its beautiful lavender hue from Hawaiian sweet potatoes. It’s a refreshing dessert that’s easy to make and it’s not too sweet!

This recipe serves 4 to 6 but you can easily double up the recipe to serve more people. You can also halve the recipe to make a smaller batch. If you plan to halve the recipe, I recommend cooking the tapioca pearls with 5 cups of water. When I tested a half batch, I found that 4 cups of water was not enough.

I like adding sliced strawberries to the pudding for some sweet and slightly tart flavor. Feel free to use whatever fruits you like.

Prep Time15 minutes mins

Cook Time45 minutes mins

Chilling Time2 hours hrs

Ingredients

• 8 cups (1.97kg) water, plus more for steaming sweet potatoes
• 3/4 cup (155g) small tapioca pearls, (see note 1)
• 1 pound (455g) Hawaiian purple sweet potatoes, (see note 2)
• 1 cup (230g) whole or low-fat milk, can sub with oat milk
• 1 cup (225g) full-fat canned coconut milk, (see note 3 on what to do with leftover coconut milk)
• 5 tablespoons honey, divided, add more to taste
• 1 1/4 to 1/2 cups (165g to 200g) sliced strawberries

Instructions

Cook Pearls

• Add the water to a pot or large saucepan and bring it to boil over high heat. DO NOT add the tapioca pearls when the water is still cold (see note 4). Reduce the heat slightly to medium-high and add the tapioca pearls. Give the pearls a quick stir. Cook the pearls for 15 minutes and turn off the heat. The pearls will be translucent around the exterior with solid white specks in the center. Cover the pot with a lid and let the pearls sit for another 10 to 15 minutes, until the pearls look completely translucent. It’s okay if a few pearls here and there still have tiny white specks in the center.
  
• Drain the pearls and rinse them under cold water. Transfer them to a large bowl with ice water or cold tap water. Submerging the pearls completely in cold water helps them to cool faster and makes them less sticky. Let that sit while you prepare the other components of the tapioca pudding.

Steam Sweet Potatoes

• Add a steaming rack into the center of a large wok. Fill the wok with water, until the water level nearly reaches the top of the steaming rack. Cover the wok and bring the water to boil. If you have an alternate steaming setup, feel free to use that!
• Place the sweet potatoes on a plate, set the plate on top of the steaming rack, and cover the wok. Steam the sweet potatoes for 25 to 30 minutes, until you can easily pierce the flesh with a fork. You can speed up the steaming process by slicing the sweet potatoes before steaming.
  
• Let the sweet potatoes cool slightly before peeling them. You’ll need about 3/4 cup (200g) of mashed sweet potatoes, which is about 2 medium-sized sweet potatoes. Save the rest of the cooked sweet potatoes and slice them into bite-sized cubes.
  

Make Puree

• Heat the milk and coconut milk in a saucepan. Do not cover the saucepan with a lid as the milk boils over very easily. Right when the milk comes to a boil, turn off the heat. Add 3 tablespoons of honey, stir, and let the milk cool for 5 to 10 minutes.
• Pour the milk into the bowl of a high-speed blender. Add the mashed sweet potatoes and blend everything until smooth. The puree will taste very sweet at this stage, so wait until you add the tapioca pearls before assessing the overall sweetness of the pudding.

Finish Tapioca Pudding

• Drain the cooled tapioca pearls and transfer to a large bowl. Drizzle 2 tablespoons of honey over the pearls. Toss to coat the pearls with the honey. If you accidentally added all 5 tablespoons of the honey into the warmed milk, don’t worry. Just skip the honey at this stage.
• Add the sweet potato puree to the bowl and stir to incorporate. Finally, add the cubed sweet potato and sliced strawberries and stir again.
  
• You can eat the purple sweet potato tapioca pudding right away. However, I find pudding more refreshing after it’s been chilled for at least 1 to 2 hours. Feel free to serve it at your preferred temperature. Serve the tapioca pudding in bowls, wide mouth mason jars, or glasses!

Notes

1. Small Tapioca Pearls: You can usually find small tapioca pearls in Asian grocery stores. Bob’s Red Mill also produces these tapioca pearls. Use their store finder to find a grocery store that sells them.
2. Purple Sweet Potatoes: For the puree, I like to use Hawaiian (or Okinawan) purple sweet potatoes with pale yellow skins. I find that Hawaiian purple sweet potatoes have better flavor than the ones with orange/brown skins, like the Stokes purple sweet potato. I usually find Hawaiian purple sweet potatoes in Asian grocery stores.
3. Leftover Coconut Milk: If you opened a can of coconut milk for this recipe, you’ll likely have some leftover. Here’s my post on ways you can use leftover coconut milk!
4. Do Not Add Tapioca Pearls to Cold Water: The tapioca pearls will melt together if you add them when the water is cold or insufficiently heated through. Wait until the water boils before adding the pearls.
5. Why I Boil the Milk: It’s not completely necessary to boil the milk. However, when developing the recipe for my mango tapioca pudding, I noticed that the batches made with unboiled milk started to turn gray after a few hours. However, the mango puree tended to hold its golden color better when I used boiled milk. That’s why I recommend boiling the milk first before making the puree.
6. Why I Don’t Roast the Sweet Potatoes: I tried roasting the sweet potatoes during one of my test batches, and the roasting process browned the sweet potatoes too much. You need the sweet potatoes to look vibrant purple to give the puree its nice lavender color.

Nutrition

Serving: 1serving (1/4 of whole recipe) | Calories: 432kcal | Carbohydrates: 78.2g | Protein: 5.4g | Fat: 12.8g | Saturated Fat: 11.1g | Cholesterol: 3.1mg | Sodium: 98mg | Fiber: 4.7g | Sugar: 32.9g

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Cuisine: Asian

Category: Dessert