Tempura is a Japanese dish of vegetables or seafood dipped in a light batter and quickly deep-fried, then served hot with a dipping sauce. This vegetable version uses familiar produce and a simple ice-water batter; ingredients and styles vary across Japanese regions and households, so feel free to use the seasonal vegetables you have.
Ingredients
- 1 medium sweet potato, about 9 oz (250 g), scrubbed and sliced ¼ inch (6 mm) thick
- 1 small eggplant, about 9 oz (250 g), cut into ½-inch (1.25 cm) slices or wedges
- 1 small zucchini, about 7 oz (200 g), cut into ⅓-inch (8 mm) rounds
- 8 shiitake mushrooms, about 4 oz (120 g), stems removed
- 6 oz (170 g) green beans, trimmed
- 1 cup (125 g) all-purpose flour, plus ¼ cup (30 g) for dusting
- ¼ cup (32 g) cornstarch
- 1 cup (240 ml) ice-cold water, with a few ice cubes to keep it cold
- 6 cups (1.4 L) neutral high-heat oil, such as canola or peanut oil, for frying; the amount used depends on your pot
- 1 cup (240 ml) prepared dashi broth
- ¼ cup (60 ml) Japanese soy sauce
- ¼ cup (60 ml) mirin
- 1 teaspoon (4 g) sugar
Instructions
- Make the dipping sauce. Add the dashi, soy sauce, mirin, and sugar to a small saucepan. Bring just to a gentle simmer over medium heat, stirring until the sugar dissolves, about 2 minutes. Remove from the heat and set aside. It can be served warm or at room temperature. Dashi is a Japanese stock often made with kombu seaweed and bonito flakes; instant dashi is a convenient option. If dashi is unavailable, use unsalted vegetable broth, understanding that the sauce will taste less distinctly Japanese and less savory.
- Prepare the vegetables. Wash and dry the vegetables thoroughly; surface water can make hot oil spit and can loosen the batter. Cut them as listed, keeping the pieces reasonably similar in thickness so they cook at a similar pace. If the mushrooms are especially large, halve them. Arrange the vegetables on a tray and keep them dry while you set up the frying station.
- Set up safely and heat the oil. Choose a heavy, deep pot with room for the oil to bubble without approaching the rim. Add enough oil for a depth of about 2½ inches (6 cm), without filling the pot more than halfway. Set a wire rack over a rimmed tray nearby, and keep a slotted spoon or spider and an instant-read thermometer within reach. Heat the oil to 350°F (175°C), which usually takes 8–10 minutes. Do not leave heating oil unattended, and keep water away from the pot.
- Mix the batter just before frying. Whisk the 1 cup (125 g) flour with the cornstarch in a bowl. Pour in the ice-cold water and stir briefly with chopsticks or a fork, stopping when the dry flour is mostly moistened. Small lumps are welcome; vigorous mixing develops gluten and can make the coating heavy. Keep the bowl over a larger bowl of ice if the kitchen is warm. The batter should be thin enough to coat a vegetable lightly, not cling in a thick layer.
- Dust and dip a small batch. Sprinkle a little of the reserved flour over a few pieces of vegetables and shake off the excess. Dip them in the batter, letting extra batter drip back into the bowl. Work in small batches and batter only what will fit in the pot with plenty of space around each piece. If the batter thickens as it sits, stir it once or twice; do not try to make it perfectly smooth.
- Fry until crisp and tender. Lower the coated vegetables gently into the oil, placing them away from you. Fry in uncrowded batches, turning once if needed. Green beans and thin zucchini usually take about 2–3 minutes; shiitake and eggplant about 3–4 minutes; sweet potato about 4–5 minutes, until the center is tender when pierced. Cooking times vary with thickness and oil recovery, so use color and tenderness as cues as well as the clock. Keep the oil near 350°F (175°C); let it return to temperature between batches. Lift each batch onto the rack to drain. Avoid stacking the pieces, which traps steam and softens the crust.
- Finish and serve promptly. Continue with the remaining vegetables, checking the oil temperature before each batch. Serve the tempura as soon as possible with the dipping sauce. If you need to hold a batch briefly, place the rack in a 200°F (95°C) oven while the rest cooks; do not cover it, since trapped steam softens the coating. Turn off the burner when finished and let the oil cool completely before handling or disposing of it.
Tips
- Keep everything dry and cold. Water left on vegetables can cause splattering, while cold water helps limit gluten development in the batter. Pat mushrooms and cut vegetables dry, and add ice to the water rather than letting the batter sit at room temperature.
- Do not overmix or make the batter ahead. A few lumps are better than a smooth, elastic batter. Mix only when the oil is ready, and make another small batch if the first bowl warms up or becomes too thick.
- Control the oil temperature and batch size. Crowding the pot drops the temperature and makes the coating oily rather than crisp. A thermometer is much more dependable than judging the oil by eye. If you do not have one, fry one test piece first and adjust the heat based on whether it browns too quickly or stays pale and greasy.
- Choose practical substitutes. Button or cremini mushrooms can stand in for shiitake, though they are milder. Sweet potato, broccoli florets, bell pepper strips, and asparagus also work. Use plain vegetable broth instead of dashi if needed, but expect a simpler dipping sauce; use tamari instead of soy sauce for a wheat-free sauce, and check that the other ingredients are labeled gluten-free.
Serving Suggestions
Serve tempura immediately while the coating is crisp, with the dipping sauce in small individual bowls. A little grated daikon or finely sliced scallion on the side is a common, refreshing addition; stir it into the sauce just before dipping. Steamed Japanese rice, miso soup, and a simple cucumber salad make a fuller meal without competing with the fried vegetables. For a lighter shared meal, present the vegetables on a rack or a platter lined with paper, keeping the pieces in a single layer. Diners can dip each piece briefly rather than soaking it, which preserves more crunch. The sauce is savory and fairly salty, so use only a little at a time and add more to your bowl as needed.
Variations
Change the assortment with the season. Thin slices of lotus root, kabocha squash, asparagus, broccoli florets, or red bell pepper are all suitable; cut thick vegetables thin enough to become tender before the coating darkens. Kabocha has a firm, sweet flesh and may need a few extra minutes depending on slice thickness. Shiso leaves are another familiar option: coat one side lightly and fry briefly, since their delicate leaves cook faster than root vegetables.
For seafood tempura, add peeled and deveined shrimp, keeping them separate from the vegetables during prep and frying. Pat them dry, coat lightly, and fry until opaque and cooked through; the USDA FSIS safe minimum for seafood is 145°F (63°C), checked with a food thermometer in the thickest part. Use clean utensils and a clean plate for cooked seafood. You can also use firm white fish cut into small pieces, applying the same 145°F (63°C) safety temperature. For a wheat-free batter, substitute a gluten-free all-purpose flour blend for the all-purpose flour and use tamari in the sauce; the texture may be a little less delicate, and results depend on the blend.
Storage and Reheating
Tempura is best eaten fresh, because its thin crust loses crispness as it cools. Refrigerate leftovers within 2 hours in a covered container; cooked leftovers keep for 3–4 days in the refrigerator, although the vegetables and coating will soften. Store the dipping sauce separately. For the best reheating texture, spread the pieces in one layer on a rack or baking sheet and heat in a 400°F (200°C) oven for about 6–10 minutes, turning once if needed. Reheat leftovers to 165°F (74°C), the USDA FSIS temperature for reheated leftovers. A toaster oven works for a small portion. Avoid the microwave if crispness matters, since it tends to make the coating soft. Do not reheat the same portion repeatedly, and discard leftovers that have been left out beyond the two-hour limit.
Frequently Asked Questions
Why is my tempura coating soggy?
Common causes include wet vegetables, batter that was mixed too much, oil that is too cool, or too many pieces frying at once. Dry the vegetables well, use ice-cold water, leave lumps in the batter, and fry in small batches while keeping the oil close to 350°F (175°C). Drain pieces on a rack rather than in a pile so steam can escape.
Can I make the batter in advance?
It is better to mix it immediately before frying. As the batter sits, it warms up and can become heavier, while stirring it again may develop more gluten. You can measure the dry ingredients ahead and chill the water, vegetables, and mixing bowl so the final mixing takes only a moment.
How do I know when the vegetables are done?
The outside should be lightly crisp, not dark brown, and a thin knife or skewer should enter the thickest vegetable easily. Thin green beans and zucchini cook quickly; sweet potato and thick squash take longer. Cut vegetables evenly and fry one kind at a time if you want more consistent timing.
Can I use frozen vegetables?
Fresh vegetables are easier to keep crisp, but frozen vegetables can work if they are fully thawed and patted very dry. Ice crystals and extra moisture cause splattering and can make the batter slide off. Some frozen vegetables also soften after thawing, so handle them gently and expect a less crisp result.
Can I reuse the frying oil?
After it has cooled completely, strain the oil to remove crumbs and store it in a clean, sealed container in a cool, dark place for a short time. Reuse it only if it still smells neutral and is not unusually dark, sticky, or foamy; discard it if it smells stale or burnt. Never pour oil down the sink, and follow local guidance for disposal.
Can I make tempura without a deep-fry thermometer?
A thermometer gives the most reliable results, especially as each batch cools the oil. Without one, test with a small drop of batter: it should sizzle and rise steadily, not sink and sit or brown immediately. This is only a rough check, so keep batches small and monitor the food closely.
Related
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- Miso Glazed Salmon Recipe for a Savory-Sweet Dinner
- Japanese Omurice: Egg-Wrapped Fried Rice Recipe
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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes
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