The melt in mouth texture and natural sweetness of sweet potatoes make it one of the best vegetables to use for tempura. In this recipe I will teach you tips and tricks specifically for making tempura with Japanese sweet potato as well as 3 different ways to cut and enjoy!
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Sweet Potato Tempura
Sweet potato is a great vegetable to use to make tempura. It has a rustic reddish-purple skin and the centre is sweet, tender and almost creamy in texture. In addition to the great taste, texture and appearance, it can also be cut and presented in a number of different ways!
In this recipe, I will teach you 3 ways to cut and present sweet potato tempura!
What is Tempura?
Tempura has been part of Japanese cuisine since the 16th century. This ancient dish is most commonly made with seafood or vegetables coated in a light and crispy deep fried batter. The batter is made with a simple mixture of flour, eggs and water.
Although tempura is known around the world as a Japanese dish, tempura was introduced to Japan by Portuguese merchants. It started in Nagasaki and then spread to the east of Japan, where it became a speciality of Edo (Tokyo).
Ideally, tempura batter should be thin and lumpy. I also recommend using weak wheat flour with a low gluten content such as cake flour. (Using strong flours that are high in gluten will result in a chewy batter which is the opposite of what you'd want in tempura!)
If you want to learn how to make fail-free tempura batter, check out my tempura batter recipe with secret tips and tricks!
Japanese Sweet Potato (Satsumaimo)
Did you know that there are as many (if not more than) 14 types of sweet potato? Not only does the skin come in various colours (red, purple, brown) but even the insides can vary in colour, taste and texture.
While they are often mistaken for yams due to the similar appearance, sweet potatoes are sweeter than yams (who'd have guessed?!). They are also usually shorter and smaller in size.
In my recipe I use Japanese sweet potatoes. They are known as "satsumaimo" in Japanese (さつま芋) and "murasaki sweet potatoes" in English, which is actually the Japanese word for purple.
Satsumaimo are one of the sweetest (and most delicious!) types of sweet potato. They are also quite starchy and a lot drier than the American sweet potato.
3 ways to cut sweet potatoes for tempura
Like other tempura, you can use different cutting techniques for sweet potatoes too and the result will be completely different!
So, here are 3 ways to cut sweet potatoes for tempura!
Round slices
This is the most commonly type of cut used for sweet potato tempura. The thickness is generally between 0.7mm to 1cm.
Not only is it quick to do, but it ensures that every piece has some of that beautiful skin showing.
Simply wash the skin, cut off the ends and slice thinly with a sharp knife!
Thick Rounds
The thicker the sweet potato slices, the longer it takes to fry them, but the more slowly they are fried, the more the sweetness will be brought out. Because of the longer frying time, the batter might be a little darker than usual tempura.
If you like especially sweet sweet potato tempura, try to make it bigger and thicker!
The thickness is around 1.5cm-2cm.
Sticks
Stick-style sweet potato tempura is also a great option. This will make them a bit similar to fries but with a batter, they make a great snack!
To cut them into sticks, cut the sweet potato in half lengthways and then cut each half into sticks. Depending on how long you want your sticks to be, you can cut either vertically or horizontally. Just make sure every stick has a bit of skin on!
This type of cut is also ideal for making sweet potato tempura sushi rolls!
5 Tips and tricks to make a good sweet potato tempura at home
Making tempura might seem like a simple case of make an easy batter, dip and deep fry, but actually, I find it one of the hardest dishes to make well in Japanese cooking.
It requires a lot of attention and a slight difference in cooking can end up making a big difference in the result.
Here I will list all the tips and tricks specifically for sweet potato tempura that you can easily use at home!
Always keep the skin on
Sweet potato skins are beautifully coloured when fried and are also packed with nutrients. Without skin, it wouldn't be like sweet potato tempura.
So, leaving skin on is the norm for tempura.
Scoring the surface
To ensure balanced and even cooking, we often score the surface of the sweet potato with a shallow cross.
This is especially important if you use thick cuts of sweet potatoes.
Soak in water for at least 10 minutes
Sweet potatoes are very starchy vegetable and when exposed to air, they oxidise and become discoloured.
So once you've cut the sweet potatoes, make sure to soak them in a bowl of water for at least 10 minutes to remove starch. The water will also be slightly absorbed into the sweet potato and act as a barrier so that it doesn't absorb too much oil when it's fried.
When finished, be sure to wipe dry with kitchen paper.
Dusting with flour
As with other tempura, it's important to dust with flour so that the batter sticks to the surface better.
It is also important to dust off any excess flour to ensure an even layer. If the dusting of flour is too thick it can also cause the tempura batter to fall off, so keep it thin.
The Ideal temperature is 160C
The ideal temperature for frying sweet potato tempura is a little lower than most other kinds of tempura as it takes a lot longer to cook potatoes through.
Cook time really depends on how thick you cut the potatoes, but if it's around 1cm, cooking time will be 4-5 minutes.
Step by step recipe
Japanese Sweet Potato Tempura (さつま芋の天ぷら)
- Total Time: 1 hour
- Yield: 3-4 portions 1x
Description
How to make Japanese sweet potato tempura. (さつま芋の天ぷら) Serves 3-4
Ingredients
- 100ml cold water
- 50ml sparkling water
- 15g potato starch or corn starch
- 75g weak flour (cake flour or all purpose) + extra for dusting
- ½ tbsp Japanese egg mayonnaise (or half a small whisked egg)
- 2 ice cubes (optional)
- Oil for frying (vegetable, canola, peanut or white sesame)
- 3 Japanese sweet potatoes (alternatives: American sweet potato)
Instructions
- Measure out 100ml of water into a jug and place it in the fridge for 20-30 minutes. Place sparkling water in the fridge too. (Preferably an unopened bottle.)
- Sift 15g potato starch and 75g cake flour into a bowl. Mix them together and place the bowl in the fridge for 20-30 minutes.
- While your tempura batter ingredients are chilling, wash the surface of your sweet potato, cut off the ends and slice according to your preferred method from the post above. (Thin rounds, thick rounds or sticks/wedges.) Make sure every piece has some skin left on. (If using thick rounds, cut a shallow cross pattern on the front and back of each piece.)
- Soak the cut pieces in cold water for 10 minutes.
- Once your batter ingredients have been chilling in the fridge for 30 minutes, start preheating your oil to 160°C (32o°F).
- In a bowl (or jug), add a few tbsp of the chilled water and ½ tbsp of mayonnaise. Mix until well combined, this loosens up the mayo. (Alternatively, whisk a small egg in a separate bowl and add half to the water instead.)
- Pour the rest of the chilled water and 50ml of chilled sparkling water into the bowl.
- Add the flour/starch to the water one third at a time, gently drawing crosses through the mixture with the chopsticks to incorporate it. (Do not whisk or over mix.)
- Test your oil by adding a drop of batter, if it sizzles and floats you're ready to fry.
- Add a couple of ice cubes to the batter and mix to make it extra cold. (optional)
- Dry the sweet potato pieces with kitchen paper and coat them thin layer of flour.
- Dip them in the batter and then carefully place them into the oil. Make sure not to overfill the pot. (Keep the batter in the fridge or freezer between batches.)
- For thin rounds or sticks fry for 4-5 minutes, turning over half way through. For thick slices, fry for 6-7 minutes or until you can easily pierce the centre with a skewer.
- Once cooked, place on a wire rack to allow the excess oil to drip off.
- Serve and enjoy!
Notes
You can enjoy sweet potato tempura with tentsuyu dipping sauce or salt.
Sweet potato tempura can be eaten as a side or served on top of udon noodles, soba noodles or on top of rice (tendon/tempura donburi).
If you make the stick type, sweet potato tempura sushi rolls are also gaining popularity online and are a great sushi option for vegetarians!
- Prep Time: 15 minutes
- Chilling time: 30 minutes
- Cook Time: 15 minutes
- Category: Vegetable
- Method: Deep fry
- Cuisine: Japanese
Keywords: Japanese sweet potato tempura, sweet potato tempura recipe, how to make sweet potato tempura, sweet potato tempura, tempura sweet potatoes, how to make tempura sweet potato, what is sweet potato tempura, Japanese sweet potato tempura, purple sweet potato tempura, murasaki sweet potato tempura,
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