Make the dipping sauce (tentsuyu): In a small saucepan, combine vegan dashi, soy sauce, mirin, sugar. Bring to a gentle simmer, stir until the sugar dissolves, then set aside to cool.
Prepare the vegetables: Peel and slice the sweet potato into thin disks (about ½ cm thick).
Cut the aubergine into 1 cm rounds.
Slice the mushrooms about 1 cm thick.
Cut the nori sheet into 8 small squares (roughly 2 x 2 inches).
Trim the broccoli stems to fit your frying pan.
Peel and grate the daikon and/or ginger, and thinly slice the spring onion (optional, for garnish).
Prepare the batter: In a mixing bowl, whisk together plain flour and cornstarch until combined. Place some extra plain flour in a separate bowl for dusting. Add sparkling water to the flour mix and stir gently with chopsticks—do not overmix; lumps are fine. Add a few ice cubes to keep the batter very cold.
Heat the oil and fry the vegetables: Pour neutral oil into a deep pan to about 4 cm depth. Heat to 180°C (350°F). Lightly dust each vegetable (except the nori) in flour, dip into the batter, and carefully place into the hot oil. Fry in small batches until crisp and light golden.
Drain and serve: Transfer cooked tempura to a paper-towel-lined plate to drain then arrange on a platter.
Serve with small dishes of dipping sauce and let everyone customise with a pinch of grated ginger, grated daikon, and spring onions. Dip, crunch, and enjoy while it’s hot, light, and irresistibly crisp.
Notes
Keep the batter cold: Cold batter hitting hot oil is the secret to light, crispy tempura. Add ice cubes as needed.
Fry in small batches: Overcrowding lowers the oil temperature and makes tempura soggy.
Neutral oil is best: Use vegetable, sunflower, or canola oil. Avoid olive oil as it is too strong in flavor.
Vegan dashi options: Use kombu and shiitake mushroom dashi as a base (see our vegan dashi recipe).
Make it gluten free: Swap the plain flour for rice flour or a gluten free flour blend.
Best eaten fresh: Tempura does not keep its crispiness for long, so it is best enjoyed immediately after frying.