A recipe for Sweet Potato Tempura! Purple sweet potatoes are thinly sliced, lightly coated in batter, and fried until golden.
Chad and I had a date night a couple of months ago at Genki Izakaya in Fairfax, Virginia. Everything we tried was fantastic, but I especially loved the Japanese-style sweet potato fries with miso honey mustard.
I came across purple sweet potatoes while at Wegmans and was reminded again of those incredible sweet potato fries. This became the inspiration behind today’s Purple Sweet Potato Tempura (紫芋の天ぷら) recipe!
In this version, sliced purple sweet potatoes are coated in a light tempura batter and deep-fried until tender with a crisp, golden coating.
I paired the Sweet Potato Tempura with a Miso Honey Mustard Dipping Sauce similar to the one at the restaurant. You can also serve the slices with a traditional Tentsuyu (Tempura Dipping Sauce), use them as a topping for udon or other noodle soups, or as a part of a bento.
Purple Sweet Potatoes
I made this recipe with purple sweet potato (both skin and interior) to get that distinctive purple hue to contrast with the lighter color of the tempura batter.
For those in Northern Virginia, I came across the purple sweet potatoes at Wegmans in Chantilly, Virginia. You can go with your favorite variety or other types of sweet potatoes based on availability.
Wash the sweet potatoes well before using, but do not peel. Cut the sweet potatoes in about 1/4 inch (6 millimeter) slices. Any thicker and the center may not cook through before the batter becomes golden.
Pat the slices dry with a towel on all sides before dipping into the batter.
A Few Sweet Potato Tempura Tips
I did not add any salt to the batter or to the sweet potatoes. You will get that saltiness from the miso honey mustard dipping sauce. If not using a dipping sauce, sprinkle a little flaky sea salt over the tempura after frying.
Do not bring together the dough until immediately before frying. Make sure to use ice-cold water.
The batter is best mixed very briefly with chopsticks. Take care to not over-mix or the texture will become too chewy. There should still be a few small lumps.
Chopstick Chronicles added black sesame seeds to her batter. This is a fun option to add even more flavor and a bit of contrast.
If the batter is too thick when coating the sweet potato slices, mix in a little more cold water (not too much!). If too thin to stick to the slices, add a little more flour.
Fry the sweet potato slices in batches, taking care to not crowd the pan. Bring the temperature of the oil back up to around 360˚F (185˚C), no higher, before frying the next batch. If the oil is too cold, the slices will soak in the oil and not become tender. If too hot, the batter will brown before the interior gets a chance to cook.
Have any leftover tempura flakes (Tenkasu)? Scoop them out between batches, drain on paper towels, and save them to use as a topping for noodles such as Hiyashi Tanuki Udon.
Looking for more sweet potato recipes?
Try my:
Sweet Potato Tempura Recipe
Adapted from Chopstick Chronicles
Sweet Potato Tempura
Ingredients
Miso Honey Mustard Dipping Sauce:
- 1 1/2 tablespoons (22 milliliters) white wine vinegar
- 1 1/2 tablespoons (22 milliliters) Japanese mayonnaise
- 1 1/2 tablespoons (22 milliliters) Dijon mustard
- 1 tablespoon (15 milliliters) sunflower oil
- 1 tablespoon (15 milliliters) honey
- 2 teaspoons white miso
- 1/4 teaspoon freshly ground black pepper
Sweet Potato Tempura:
- 1 1/2 pounds (680 grams) sweet potato unpeeled
- Vegetable oil for deep-frying
- 3/4 cup (177 milliliters) ice cold water
- 1 large egg yolk
- 3/4 cup (90 grams) cake flour
- 2 tablespoons (15 grams) cornstarch
Instructions
To make the Miso Honey Mustard Dipping Sauce:
- In a medium bowl, whisk together the white wine vinegar, mayonnaise, Dijon mustard, sunflower oil, honey, white miso, and black pepper until smooth.
- Adjust seasonings to taste.
- Set aside or cover and refrigerate for up to 2 days if not using immediately.
To make the Sweet Potato Tempura:
- Cut the unpeeled sweet potatoes into 1/4 inch (6 millimeter) thick discs. Pat dry on all sides with a paper towel to make sure no moisture remains.
- Pour the oil in a large saucepan or wok to about 2 inches (5 centimeters) deep and heat to 360˚F (185˚C).
- In a large bowl, beat together the water and egg yolk until frothy.
- Whisk in the flour and cornstarch using chopsticks until just combined, but not completely smooth, no more than a minute.
- Dip a sweet potato slice into the batter to coat completely, allow any excess to drip off, then place immediately in the heated oil. Repeat with more sweet potatoes, being careful not to crowd the pan.
- If the batter is too thick when coating the sweet potatoes, mix in a little more ice cold water. If too thin and falling off, mix in a little more flour.
- Fry until golden on both sides, 3-5 minutes, then transfer to a towel-lined plate or rack. Remove any small leftover fried pieces of tempura batter as well.
- Repeat with remaining sweet potato slices, letting the oil get back to 360˚F (185˚C) between batches.
- Serve immediately with the Miso Honey Mustard Dipping Sauce or Tentsuyu (Tempura Dipping Sauce).
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