Vegetable Tempura Recipe

Make dipping sauce (mentsuyu style)

Combine soy sauce (0.5 cup), mirin (2 tbs) and dashi stock or water (0.5 cup) in a small bowl. Stir and refrigerate until ready. Adjust to taste—add a pinch of sugar if you prefer it sweeter.

Prepare batter

Place 1 cup ice cold water in a bowl and add 3 ice cubes to keep it very cold. In a separate bowl whisk 1 large egg lightly, then pour the egg into the cold water. In a medium bowl sift together 1 cup all-purpose flour, 1/4 cup rice flour (or cornstarch), 1/4 tsp baking soda (optional) and 1/2 tsp salt. Just before frying, add the dry mix to the egg-water and stir very briefly with chopsticks or a fork—do not overmix. Leave some lumps; batter should be slightly runny and cold.

Prepare vegetables

Slice the onion into 1/4-inch thick rings; separate into petals. Cut kabocha squash into 1/8–1/4-inch thin slices (remove seeds and hard skin if desired but leaving skin is traditional). Peel and slice Japanese yam (nagaimo) into 1/8-inch rounds or sticks; if sticky, rub lightly with a little oil or rinse and pat dry. Peel and cut the carrot on a diagonal into 1/8-inch slices. Seed the red bell pepper, then cut into strips about 1/2-inch wide. Pat all vegetables dry with paper towels—moisture will cause oil splatter and make batter less crisp.

Heat oil

Pour 1.5 cups vegetable oil into a heavy-bottomed pot or deep fryer. Heat to 350°F (175°C). If you don’t have a thermometer, test by dropping a small bit of batter into the oil: it should sizzle and rise to the surface quickly without browning immediately.

Fry vegetables

Working in small batches (do not crowd), dip each vegetable piece briefly into the batter to coat (shake off excess lightly) and slide gently into the hot oil. Fry onion petals for 60–90 seconds until puffed and light golden. Fry thin kabocha and carrot slices for 60–90 seconds. Fry Japanese yam pieces for 60–90 seconds (adjust time for thickness). Fry red pepper strips 45–60 seconds. Keep the oil temperature steady between 330–360°F (165–180°C). Remove with a slotted spoon or spider and drain on a rack or paper towels.

Keep crisp between batches

If frying many batches, keep finished tempura on a wire rack in a single layer in a warm oven at 200°F (95°C) for up to 10–15 minutes to stay crisp. Do not stack pieces directly on paper towels or they will steam and soften.

Season immediately with a light sprinkle of fine sea salt or tempura/matcha salt while the pieces are hot so the seasoning sticks.

Serve the tempura hot with the dipping sauce alongside and lemon wedges if desired. Recommend advising diners to dip sparingly so the batter stays crisp. Leftovers can be reheated briefly in a 375°F (190°C) oven for 4–6 minutes, but texture is best fresh.