Black sesame tempura asparagus with miso mayo

Method

1. Heat about 4cm oil in a wide, deep frying pan or casserole to 170°C (if you don’t have a digital probe thermometer, it’s ready when a bread cube dropped into the oil turns golden in about 25 seconds).
2. Mix the ingredients for the miso mayo in a bowl (see Make Ahead).
3. Put the tempura batter mixture into a gratin dish long enough to hold the asparagus, then whisk in the black sesame seeds and chilled sparkling water until almost smooth (a few lumps are okay).
4. Put 4-6 asparagus spears at a time in the batter and turn to coat. Fry in batches for about 2 minutes, turning occasionally. Remove with tongs and set on a wire rack over a baking sheet. Repeat with the rest of the asparagus. Drizzle with miso mayo, sprinkle with black and white sesame seeds and serve with lime wedges.